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1.
a) -[ -345 + 1234 - 2014] - (345 - 1234)
= 345 - 1234 + 2014 - 345 + 1234
= ( 345 - 345) + ( -1234 +1234) +2014
= 0 + 0 + 2014 = 2014
b) ( -31) . 47 + ( -31) . 52 + ( -31)
= (-31) . ( 47 + 52 +1)
= (-31) . 100 = -3100
c) 654 +{ 374 - [ 654 - ( +126)]}
= 654 + [ 374 -( 654 - 126)]
= 654 + ( 374 - 654 + 126)
= 654 + 374 - 654 + 126
= ( 654 - 654 ) + ( 374 + 126 )
= 0 + 500 = 500
mik tìm đc câu trả lời rùi điểm này là tặng cho bạn đã trả lời cho mik❤
a) -329 + ( 27 - 111 ) - ( 127 - 440 )
= -329 + 27 - 111 - 127 + 440
= -329-111 -127 + 27 +440
= -440 - 100 +440
=-100
b) ( 157 - 984 ) - ( 16 - 74 ) - ( 374 - 243 )
= 157 - 984 - 16 +74 - 374 + 243
= 157 + 243 - 984 - 16 -374 + 74
= 400 - 1000 - 300
= 100 - 1000
= -900
1) a) \(35.34+35.58+65.75+65.45\)
\(=35\left(34+58\right)+65\left(75+45\right)\)
\(=35.92+65.120\)
\(=3220+7800=11020\)
b) \(39,8+60,2+21,8-100\)
\(=\left(39,8+60,2\right)-100+21,8\)
\(=100-100+21,8=0+21,8=21,8\)
c) \(36.28+64.49+36.82+41.64\)
\(=36\left(28+82\right)+64\left(49+41\right)\)
\(=36.110+64.90\)
\(=3960+5760\)\(=9720\)
Bài 2. Tính nhanh
a) 27 + (-2019) + (-27)
= 27 -2019 -27
=(27 - 27) -2019
=0-2019
= -2019
d) (-102) – (345 – 102)
= -102 - 345 +102
= (102 - 102) -345
= 0-345
= -345
b) (-10) + 23 + (-20) + 30
= -10 +23-20+30
= -(10+20) +23 +30
= -30 +23 +30
= (30-30) +23
= 0 +23
= 23
e) (12 + 34 – 56) – (12 – 56)
= 12 +34 -56 -12 +56
= (12-12) + (56-56) +34
= 0+0 +34
= 34
c) (-2).125.(-5).(-8).(+17)
=[(-2) . (-5)] . [ 125.(-8)] . (+17)
= 10 . (-1000).(+17)
= - 10000 . 17
= - 170000
f) 37.(-345) – 345.(-47)
= -345 . (37-47)
= -345.(-10)
=3450
a) = 25 x 32 + 25 x 47 - 32 x 25 + 32 x 47
= 25 x 47 - 32 x 47
= -329
b) = 2 - 12 - 6
= -16
c) = 2 x (-7) - 10 + 1
= -14 - 10 + 1
= -23
d) = -6 - (-1) + (-2)
= -7
- \(=\left(-23+27-13+47-23+37-13+47\right):45\)\(=\left(-23.2-13.2+27.2+47.2\right):45=\left(-72+148\right):45=\frac{76}{45}\)
- \(=59:\left(111-522+115-23\right)=59:\left(-319\right)\)
a) 2575+37-2576-29=(2575+2576)-29+37=-1-29+37=-30+37=7
b)34+35+36+37-14-15-16-17=(34-14)+(35-15)+(36-16)+(37-17)=20+20+20+20=80
X
a,2575+37-2576-29=37+[(2575-2576)-29]=37+(-30)=7
b,34+35+36+37-14-15-16-17=(34-14)+(35-15)+(36-16)+(37-17)=20+20+20+20=80
\(\text{Phần a nên sửa đề thế này :}\) \(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)
\(\text{Giải :}\)
\(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)
\(=\frac{1}{7}\left(\frac{-3}{8}+\frac{-13}{8}\right)\)
\(=\frac{1}{7}.\left(-2\right)\)
\(=\frac{-2}{7}\)
\(\frac{3}{5}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)
\(=\frac{3}{5}.\left(\frac{1}{46}.13\right)-\frac{1}{10}.\frac{32}{46}\)
\(=\left(\frac{3}{5}.13\right).\frac{1}{46}-\left(\frac{1}{10}.32\right).\frac{1}{46}\)
\(=\frac{39}{5}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)
\(=\frac{78}{10}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)
\(=\left(\frac{78}{10}-\frac{32}{10}\right).\frac{1}{46}\)
\(=\frac{46}{10}.\frac{1}{46}\)
\(=\frac{1}{10}\)
Lời giải:
a.
$(-47)+316+(-111)-16-503=-47+316-111-16-503$
$=(316-16)-111-(47+503)=300-111-550=-111-(550-300)=-111-250$
$=-(111+250)=-361$
b.
$(-1460)+(-345)-(-578)+460-(-365)+(-178)$
$=-1460-345+578+460+365-178$
$=-(1460-460)+(365-345)+(578-178)$
$=-1000+20+400=-(1000-400)+20=-600+20=-(600-20)=-580$