1.-14*63+(-14)*37=-14*(63+37)=-14*100=-1400

2.-21*21+21*(-79)=21*[-21+(-79)]=21*(-100)=-2100

cho mình nha!Thank you!

1. = - 14* ( 63 + 37) 

    = -14*100

    = -1400

2. = [ -21 + ( -79) ] *21

   = ( - 100) * 21

   = - 2100

1. = - 14.( 63 + 37 ) = - 14 . 100 = - 1400

2. = 21.[ ( - 21 ) + ( - 79 ) ] = 21.( - 100 ) = - 2100

2 . 17 . 12 + 4. 6 . 21 + 8 . 3 . 62

= ( 2. 12 ) . 17 + ( 4 . 6 ) . 21 + ( 8 . 3 ) . 62

= 24 . 17 + 24 . 21 + 24 .62

=  24. ( 17 + 21 + 62 )

= 24 . 100

= 2400

37 . 24 + 37 . 76 + 63 . 79 + 63 . 21

= 37 . ( 24 + 76 ) + 63 . ( 79 + 21 ) 

= 37 . 100 + 36 . 100

= ( 37 + 63 ) . 100

= 100 . 100

= 10000

   2 . 17 . 12 + 4. 6 . 21 + 8 . 3 . 62

= ( 2. 12 ) . 17 + ( 4 . 6 ) . 21 + ( 8 . 3 ) . 62

= 24 . 17 + 24 . 21 + 24 .62

=  24. ( 17 + 21 + 62 )

= 24 . 100 = 2400

   37 . 24 + 37 . 76 + 63 . 79 + 63 . 21

= 37 . ( 24 + 76 ) + 63 . ( 79 + 21 ) 

= 37 . 100 + 36 . 100

= ( 37 + 63 ) . 100

= 100 . 100 = 10000

      ~ Chúc bn học tốt!! ^^ ~

2 câu cuối mik ko biết lm mong bn thông cảm nha ><

\(\frac{21.19+19.79}{38.50}\)

\(=\frac{19.\left(21+79\right)}{38.50}\)

\(=\frac{19.100}{38.50}\)

\(=\frac{19.2.50}{19.2.50}\)

\(=1\)

21 × 19 + 19 × 79 / 38 × 50

= 21 × 19 + 0,79

= ( 20 + 1 ) ×  19 + 0,79

= 20 × 19 + 1 × 19 + 0,79

= 380 + 19 + 0,79

= 399 + 0,79

= 399,79

\(\frac{21\cdot19+19\cdot79}{38\cdot50}\)

\(=\frac{19\left(21+79\right)}{38\cdot50}\)

\(=\frac{19\cdot100}{38\cdot50}\)

\(=\frac{19\cdot50\cdot2}{19\cdot2\cdot50}=1\)

= (79+21)+(82+18)

=40+100

=140

k mk nhé

= (79+21) + (82+18)

= 100 + 100

= 200

cám ơn nhé

a,(-8-12):/-5/=-20:5=4(ban oi con nay ko tinh nhanh dc)

b,(-49)-/-145/+(-2017)+/245/+(-51)=(-49+am 51)-145-2017+245=-100+100-2017=0-2017=-2017

c lam theo con gai obama minh ko chac ban tinh lai ket qua xem

d,-99(2-678)-678.99=-99.676+678.(-99)=-99.676+678.(-99)=-99(676+678)=-99.1345=-133155(tinh lai ket qua nha)

c) 79.l-39l -21.l-39l

=79.39 -21.39

=39.(79 -21)

=39.58=3364

a) (- 8 - 12 ) : | - 5 | = - 20 : 5 = - 4

b) ( - 49 ) - | - 145 | + ( - 2017 ) + | 245 | + ( - 51 )

=  - 49  - 145 - 2017 + 245 - 51

= ( - 49 - 51 ) + ( - 145 + 245 ) - 2017

= - 100 + 100 - 2017

=  0 - 2017 = - 2017

c) Bạn cho đề rõ ra nhé !!!!

d) - 99 . ( 2 - 678 ) - 678 . 99

= - 99 . ( - 676 ) - 67122

= 66924 - 67122

= - 198

\(M=896+892+888+...+24\)

\(M=\frac{\left(896+24\right).219}{2}=100740\)

\(N=18.21+21+21.79\)

\(N=21.\left(18+1+79\right)=21.100\)

\(N=2100\)

b,

N=18x21+21+21x79

N=18x21+21x1+21x79

N=(18+1+79)x21

N=98x21

N=2058

b ) 

=(18 .21) +21 + (21.79 ) 

= 18 .20 + 18.1 +  21  + 20 . 79 + 79

= 360 + 18 + 21 + 1580 + 79 =  2058

\(50.\left(21+79\right)+17.\left(31+69\right)\)

\(\Rightarrow50.100+17.100\)

\(\Rightarrow100.\left(50+17\right)\)

\(=100.67=6700\)

50. (21+79) + 17. (31+69)

= 50.100 + 17. 100

= 100. (50+17)

= 100.67 

= 6700

(23 + 77) + ( 56 + 144) + ( 79 + 21)

= 100 + 200 + 100

= 400. 

k cho mik nhé! Thanks

23 + 56 + 79 + 144 + 77 + 21

= ( 23 + 21 ) + ( 79 + 77 ) + ( 56 + 144 )

= 44 + 156 + 200

= 200 + 200

= 400