1. Thực hiện phép tính ( tính nhanh nếu có thể ) :
a) [( -52 ) + 18] . ( -7 ) b) ( 18 - 3 . 21 ) + ( -24 )
c) ( -40 ) : 8 + 3 . ( 21 - 33 ) d) ( -4 ) . 125 . ( -25 ) . ( -6 ) . ( -8 )
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a,\(\left[\left(-52\right)+18\right].\left(-7\right)\)
\(=\left(-34\right).\left(-7\right)\)
\(=238\)
b,\(\left(18-3.21\right)+\left(-24\right)\)
\(=>\left(18-63\right)-24\)
\(=>-45-24\)
\(=-\left(45+24\right)\)
\(=-69\)
a) [ ( -52) + 18] x ( -7) b)(18 -3 x 21) + (-24)
=(-34) x (-7) =(18-63)-24
=238 =-69
c)(-40) : 8 + 3 x (21 - 33) f) 48 x 15 - 257 x 48
= -5+3 x (-12) =48 x ( 15-257)
= -5-36 =48 x (-242)
= -41 =-11616
a: \(=\dfrac{7}{2}\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}-\dfrac{8}{13}\right)=\dfrac{7}{2}\cdot\left(-3-\dfrac{3}{13}\right)=\dfrac{7}{2}\cdot\dfrac{-42}{13}=\dfrac{-147}{13}\)
b: \(=-12+\dfrac{8}{9}-\dfrac{5}{18}=\dfrac{-216}{18}+\dfrac{16}{18}-\dfrac{5}{18}=\dfrac{-205}{18}\)
c: \(=\dfrac{45}{4}-\dfrac{19}{7}-\dfrac{21}{4}=6-\dfrac{19}{7}=\dfrac{23}{7}\)
d: \(=\dfrac{-1}{4}\left(\dfrac{152}{11}+\dfrac{68}{11}\right)=\dfrac{-1}{4}\cdot20=-5\)
a) 2345 − 1000 : [19-2(21-18) 2 ]=2345-1000:1=1345
b) 205 − [ 1200 − ( 4 2 − 2.3 ) 3 ]=205-( 1200 − 1000 ) = 5
c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)
\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)
\(=1-2=-1\)
Giải:
a)-1/12+4/3=-1/12+16/12=15/12=5/4
b)(-4/14-3/15)-(1/5-20/35-(-1)).7
=-17/35-22/35.7
=-17/35-22/5
=-171/35
c)3/5+-5/20+30/75+-7/4
=3/5+-1/4+2/5+-7/4
=(3/5+2/5)+(-1/4+-7/4)
=1+-2
=-1
d)5/6.-12/14+7/13
=-5/7+7/13
=-16/91
e)2/-9-5/-36-1/4
=-1/12-1/4
=-1/3
f)2/23+-5/12+7/18+21/23+-7/12
=(2/23+21/23)+(-5/12+-7/12)+7/18
=1+-1+7/18
=7/18
a: =-1/3+1/3=0
b: \(=\dfrac{4}{11}\left(-\dfrac{2}{7}-\dfrac{4}{7}-\dfrac{1}{7}\right)=\dfrac{4}{11}\cdot\left(-1\right)=-\dfrac{4}{11}\)
c: \(=10+\dfrac{5}{9}-3-\dfrac{5}{7}-4-\dfrac{5}{9}=3-\dfrac{5}{7}=\dfrac{16}{7}\)
d: \(=\dfrac{1}{3}+\dfrac{7}{4}-\dfrac{7}{4}+\dfrac{4}{5}=\dfrac{1}{3}+\dfrac{4}{5}=\dfrac{5+12}{15}=\dfrac{17}{15}\)
a: =-1/3+1/3=0
b: =411(−27−47−17)=411⋅(−1)=−411=411(−27−47−17)=411⋅(−1)=−411
c: =10+59−3−57−4−59=3−57=167=10+59−3−57−4−59=3−57=167
d: =13+74−74+45=13+45=5+1215=1715
1: 0,35*12,4=0,35*2,4+0,35*10=3,5+0,84=4,34
2: =0,1-2,34=-2,24
3: =5-2,9=2,1
4: \(=2,5\left(10,124-0,124\right)=10\cdot2,5=25\)
5: =-3/7+1/13
=-39/91+7/91
=-32/91
6: =-1/3+1/3=0
a) =-34.-7
=238
b) =-45-24
=-69
hacker 2k6
\(a,\left[\left(-52\right)+18\right].\left(-7\right)\)
\(=\left[-52+18\right].\left(-7\right)\)
\(=-34.\left(-7\right)=34.7\)
\(=238\)
\(b,\left(18-3.21\right)+\left(-24\right)\)
\(=\left(18-63\right)-24\)
\(=18-63-24=-69\)