Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
A)
- Từ 1 đến 9 có 9 số,gồm 9 chữ số.
- Từ 10 đến 99 có 90 số,gồm 180 chữ số.
- Từ 100 đến 200 có 101 số,gồm 202 chữ số.
Số chữ số cần dùng để đánh số trang của 1 quyển sách dày 200 trang là:
9 + 180 + 202 = 391 ( chữ số )
( mik cx ko biết có đúng ko nx,nhưng theo mik là zậy )
Chúc học tốt nha !!!
a/ Đánh số trang từ 1 đến 9 cần số chữ số là :[ (9 - 10 ) : 1 +1 ] x 1 =9 ( chữ số )
Đánh dấu trang từ 10 đến 99 cần số chữ số là : [(99 - 10) : 1 +1 ] x 2 =180 ( chữ số )
Đánh dấu trang từ 100 đến 200 cần số chữ số là : [ ( 200 -100 ) : 1 + 1 ] x3 = 303 ( chữ số )
Đánh dấu trang một quyển sách gồm 200 trang cần số chữ số là :9+180+303= 492 ( chữ số )
Đáp số : 492 chữ số.
Bài 1:
Số chữ số cần có để đánh hết số trang từ 3 đến 9 là:
(9 - 3) : 1 + 1 = 7( chữ số )
Số chữ số cần có để đánh hết số trang từ 10 đến 99 là:
[(99 - 10) : 1 + 1] x 2 =180 (chữ số )
Số chữ số cần có để đánh hết số trang từ 100 đến 132 là:
[(132 - 100) : 1 + 1] x 3 = 99 (chữ số )
Số chữ số cần có để đánh hết số trang của cuốn sách đó là:
7 + 180 + 99 = 286( chữ số )
ĐS: ___________________
Bài 2:
Từ trang 1 → trang 9 có 9 trang và cần 9 chữ số
Từ trang 10 → trang 99 có 90 trang và cần 180 chữ số.
Số chữ số dùng cho các trang có 3 chữ số là : 612 - 180 - 9 = 423 (chữ số)
Số trang có 3 chữ số là : 423 : 3 = 141 (trang)
Quyển sách đó có số trang là : 141 + 9 + 90 = 240 (trang)
ĐS: _______________________________
B1:
Giả sử tính cả 2 trang đầu ta có:
Từ trang 1 đến trang 9 cần dùng:9 chữ số
Từ trang 10 đến trang 99 cần dùng:90.2=180 chữ số
Từ trang 100 đến trang 132 cần dùng:33.3=99 chữ số
Vậy cần dùng tất cả:99+180+9=288 chữ số
Nếu không tính 2 trang đầu ta cần dùng:288-1-1=286 chữ số
Đ/s:.....
B2:
Từ trang 1 đến trang 9 cần dùng 9 chữ số ứng với 9 trang
Từ trang 10 đến trang 99 cần dùng 180 chữ số và có 90 trang
Số chữ số dùng để viết các số có 3 chữ số là:612-9-180=423(chữ số)
Số trang có 3 chữ số là:423:3=141(trang)
Quển sách đó dày:141+9+90=240(trang)
Đ/s:....
1/Để đánh số trang của quyển sách đó cần:
\([\left(9-1\right):1+1]+[\left(99-10\right):1+1]\times2+[\left(248-100\right):1+1]\times3=636\)(chữ số)
Bài 2:
a: \(=28\cdot300+72\cdot300=300\cdot100=30000\)
b: \(=2017-\left\{10^2-11\cdot\left[49-5\cdot8\right]\right\}\)
\(=2017-\left(100-11\cdot9\right)=2017-1=2016\)
c: Số số hạng là:
(414-1):7+1=60(số)
Tổng là:
\(\dfrac{\left(414+1\right)\cdot60}{2}=415\cdot30=12450\)
Bài 3:
b: \(\Leftrightarrow2^x\cdot9=144\)
\(\Leftrightarrow2^x=16\)
hay x=4
bn ơi !!
bt1 là 5050 công thức : số đầu cộng số cuối nhân sổ số hạng chia 2 ok
k mik nha
(=) 2x.24+2x=34
(=) 2x.(16+1)=34
(=) 2x.17 =34
(=) 2x =2
=) x = 1
vậy............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
Các số từ 1 đến 9 có 9 chữ số.
Các số từ 10 đến 99 có 90 số và có số chữ số là: 90 x 2 = 180 chữ số
Số 100 có 3 chữ số nên sẽ cần số chữ số là: 9 + 180 + 3 = 192 chữ số
Đáp số: 192 chữ số
Chúc bạn học tốt!