dễ mà nhóm số tròn rồi tính như bình thường

a) 124+(-52).124+(-124).(-47)

=124+(-52).124+124.47

=124[1+(-52)+47]

=124.(-4)=-496.

b) -55.78+13.(-78)-78.(-65)

=(-55).78+(-13).78-78.(-65)

=78[(-55)+(-13)-(-65)]

=78.(-3)=-234.

Chúc bạn học tốt!

#Huyền#

1: \(=-24\left(45-5\right)=-24\cdot40=-960\)

2: \(=-134\left(1-51+48\right)=-134\cdot\left(-2\right)=268\)

3: \(=124\left(1-52+47\right)=124\cdot\left(-3\right)=-372\)

khó quá đi!!

a.(-256).43+(-256).25-256.32                            
=(-256).43+(-256).25+(-256).32                =(-256).(43+25+32)    
=(-256).100      
-25600

Đáp án cần chọn là: C

a: \(5\cdot11\cdot18+9\cdot31\cdot10+4\cdot29\cdot45\)

\(=11\cdot\left(5\cdot18\right)+31\cdot\left(9\cdot10\right)+29\cdot2\cdot\left(2\cdot45\right)\)

\(=90\left(11+31+29\cdot2\right)\)

\(=90\cdot100=9000\)

b: \(37\cdot39+78\cdot14+13\cdot85+52\cdot55\)

\(=37\cdot39+39\cdot2\cdot14+13\cdot85+13\cdot4\cdot55\)

\(=39\left(37+2\cdot14\right)+13\cdot\left(85+4\cdot55\right)\)

\(=39\cdot65+13\cdot305\)

\(=13\left(65\cdot3+305\right)=13\cdot500=6500\)

a)

5.11.18+9.31.10+4.29.455.11.18+9.31.10+4.29.45

=90.11+90.31+2.29.90=90.11+90.31+2.29.90

=90.(11+31+2.29)=90.(11+31+2.29)

=90.100=9000

b)

37.39+78.14+13.85+52.5537.39+78.14+13.85+52.55

=37.39+39.2.14+13.5.17+13.4.5.11=37.39+39.2.14+13.5.17+13.4.5.11

=39.(37+2.14)+65.17+65.44=39.(37+2.14)+65.17+65.44

=39.65+65.(17+44)=39.65+65.(17+44)

=39.65+65.61=39.65+65.61

=65.(39+61)=65.(39+61)

=65.100=6500

1. 8 - ( 2014 - 2008 ) + 2014
= 8-2014+2008+2014
= (8-2008)+(-2014+2014)
= -2000

2. 5679 + ( 1357 - 5679 - 17
= 5679+1357-5679-17
= 1340

3. 1268 - ( 78 + 1268 ) - ( -78 )
= 1268-78-1268+78
= 0
4. 13567 - ( 15 - 27 )
= 13567+12
= 13579

5. - 48795 - ( 489 - 48795 ) + 400
= -48795-489+48795+400
= (-48795+48795)+(-489+400)
= -89
6. 15641 - ( 27 + 15641 )
= 15641-27-15641
= -27