NV
0
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Các câu hỏi dưới đây có thể giống với câu hỏi trên
NT
0
XO
28 tháng 7 2020
1) a) \(\frac{5454}{5757}-\frac{171717}{191919}=\frac{18\times3\times101}{19\times3\times101}-\frac{17\times10101}{19\times10101}=\frac{18}{19}-\frac{17}{19}=\frac{1}{19}\)
b) \(\frac{6}{5}\times\frac{7}{6}\times\frac{8}{7}\times....\times\frac{2021}{2020}=\frac{6\times7\times8\times...\times2021}{5\times6\times7\times...\times2020}=\frac{2021}{5}\)
2) \(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{45}=2\times\frac{1}{6}+2\times\frac{1}{12}+2\times\frac{1}{20}+...+2\times\frac{1}{90}\)
\(=2\times\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}\right)\)
\(=2\times\left(\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+...+\frac{1}{9\times10}\right)\)
\(=2\times\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{9}-\frac{1}{10}\right)=2\times\left(\frac{1}{2}-\frac{1}{10}\right)=2\times\frac{2}{5}=\frac{4}{5}\)
b)Vì \(a-1< a+1\)
=> \(\frac{1}{a-1}>\frac{1}{a+1}\)
LM
Lê Minh Vũ
CTVHS
15 tháng 6 2023
3 x 15 + 21 x 15 + 85 x 5
= 45 + 315 + 425
= 785
15 - 30 + 40
= 25
21 + 19 - 50 + 10
= 0
\(\dfrac{1}{5}-\dfrac{1}{4}+2\)
\(=-\dfrac{1}{20}+2\)
\(=\dfrac{39}{20}\)
\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)
\(=\dfrac{5}{12}\times\dfrac{1}{4}\)
\(=\dfrac{5}{12}\times\dfrac{3}{12}\)
\(=\dfrac{5}{48}\)
\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)
\(=-\dfrac{9}{20}\)
BD
15 tháng 6 2023
\(3\times15+21\times15+85\times5\\ =15\times\left(3+21\right)+425\\ =15\times24+425\\ =360+425\\ =785\)
\(15-30+40\\ =\left(15+40\right)-30\\ =55-30\\ =25\)
\(21+19-50+10\\ =\left(21+19\right)-\left(50-10\right)\\ =40-40\\ =0\)
\(\dfrac{1}{5}-\dfrac{1}{4}+2\)
\(=\dfrac{4}{20}-\dfrac{5}{20}+\dfrac{40}{20}\)
\(=\dfrac{\left(4+40\right)}{20}-\dfrac{5}{20}\)
\(=\dfrac{44}{20}-\dfrac{5}{20}\)
\(=\dfrac{39}{20}\)
\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)
\(=\dfrac{5}{12}\times\dfrac{1}{4}\)
\(=\dfrac{5}{48}\)
\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)
\(=\dfrac{2}{20}+\dfrac{4}{20}-\dfrac{15}{20}\)
\(=\dfrac{6}{20}-\dfrac{15}{20}\)
\(=-\dfrac{9}{20}\)
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
5 tháng 8 2023
\(\dfrac{15}{14}\): \(\dfrac{10}{21}\) \(\times\) \(\dfrac{1}{5}\) = \(\dfrac{15}{14}\) \(\times\) \(\dfrac{21}{10}\) \(\times\) \(\dfrac{1}{5}\) = \(\dfrac{5\times3\times7\times3}{7\times2\times10\times5}\) = \(\dfrac{9}{20}\)
5 \(\times\) \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) = 1 + \(\dfrac{1}{5}\) = \(\dfrac{6}{5}\)
7 : \(\dfrac{1}{5}\) - \(\dfrac{1}{5}\) = 35 - \(\dfrac{1}{5}\) = \(\dfrac{174}{5}\)
6 + \(\dfrac{1}{5}\): 2 = 6 + \(\dfrac{1}{10}\) = \(\dfrac{61}{10}\)
8 - \(\dfrac{1}{5}\) \(\times\) 7 = 8 - \(\dfrac{7}{5}\) = \(\dfrac{33}{5}\)
5 tháng 8 2023
\(\dfrac{15}{14}\) : \(\dfrac{10}{21}\) x \(\dfrac{1}{5}\) = \(\dfrac{15}{14}\) x \(\dfrac{21}{10}\) x \(\dfrac{1}{5}\) = \(\dfrac{9}{4}\) x \(\dfrac{1}{5}\) = \(\dfrac{9}{20}\)
5 x \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) = \(\dfrac{5}{1}\) x \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) = 1 x \(\dfrac{1}{5}\) = \(\dfrac{1}{5}\)
7 : \(\dfrac{1}{5}-\dfrac{1}{5}\) = \(\dfrac{7}{1}\) x \(\dfrac{5}{1}-\dfrac{1}{5}\) = \(\dfrac{35}{1}\) - \(\dfrac{1}{5}\) = \(\dfrac{175}{5}\) - \(\dfrac{1}{5}\) = \(\dfrac{174}{5}\)
6 + \(\dfrac{1}{5}\) : 2 = \(\dfrac{6}{1}\) + \(\dfrac{1}{5}\) x \(\dfrac{1}{2}\) = \(\dfrac{6}{1}+\dfrac{1}{10}\) = \(\dfrac{60}{10}\) + \(\dfrac{1}{10}\) = \(\dfrac{61}{10}\)
8 - \(\dfrac{1}{5}\) x 7 = \(\dfrac{8}{1}\) - \(\dfrac{1}{5}\) x \(\dfrac{7}{1}\) = \(\dfrac{8}{1}-\dfrac{7}{5}\) = \(\dfrac{40}{5}\) - \(\dfrac{7}{5}\) = \(\dfrac{33}{5}\)
Sai Báo Lại Mình Nha!
S
5
7 tháng 9 2018
tính trừ bt nha bạn vế thương thì cũng tĩnh ra xong mới tính nha
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
7 tháng 10 2023
a, \(x\) + \(\dfrac{1}{4}\) - \(\dfrac{3}{8}\) = \(\dfrac{7}{12}\)
\(x\) - \(\dfrac{1}{8}\) = \(\dfrac{7}{12}\)
\(x\) = \(\dfrac{7}{12}\) + \(\dfrac{1}{8}\)
\(x\) = \(\dfrac{17}{24}\)
LG
0
CM
5 tháng 9 2018
1) 2*17*9+18*540+29*18
= 18*17+18*540+29*18
= 18*(17+540+29)
= 18*586
= 10548
2) 5*{26-[3*(5+2*5)+15]/15}
= 5*{26-[3*(5+10)+15]/15}
= 5*{26-[3*15+15]/15}
= 5*{26-[45+15]/15}
= 5*{26-60/15}
= 5*{26-4}
=5*22
=110
3) (2018*2019+2019*2020)*(45*120-15*360)*(1+5+9+13+17+...+2015+2019)
= (2018*2019+2019*2020)*(15*3*120-15*120*3)*(1+5+9+13+17+...+2015+2019)
= (2018*2019+2019*2020)*0*(1+5+9+13+17+...+2015+2019)
= 0
CC
4
H
15 tháng 5 2018
( 1/3+1/6+1/10+1/15+1/21) : x =5/7
5/7: x = 5/7
x = 5/7 : 5/7
x = 1
tk giùm nhé! chúc học giỏi!
15 tháng 5 2018
ta có : ( 1/3 + 1/6 + 1/10 + 1/15 + 1/21 ) :x =5/7
=> 5/7 : x = 5/7
=> x = 5/7 : 5/7
x = 1
vậy x=1
26 tháng 8 2017
a) 15 x 21 - 16 : 4 + 7
= 315 - 4 + 7
= 311 + 7
= 318
b) 123 - 11 x 6 + 150 : 30
= 123 - 66 + 5
= 57 + 5
= 62
Mình chỉ làm đến đó thôi chứ mấy câu còn lại khó hiểu quá!Ở lớp 5 mình chưa học bao giờ.
26 tháng 8 2017
a)
=315-4+7=318
b)
=123-66+5=62
c)
=2017+5x[300-700:7]
=2017+5x[300-100]
=2017+5x200
=2017+1000
=3017
d)
=1560:[5x79-370+5x21]
=1560:[395-370+105]
=1560:130
=12
e)
=50-[12:2+34]
=50-40
=10
g)
=10-[16x5+88]:28
=10-168:28
=10-6
=4