b) 23.79 + 52.21 + 77.79 + 21.48

= 79(23+77) + 21(52+48)

= 79 .100 + 21 .100

= (79+21) .100 = 100.100 = 10000

=(23+77)*79+(48+52)*21                                                                                                                                                                                    =7900+2100 =10000

23*79+52*21+77*79+21*48

=(23+77)*79+(52+48)*21

=100*79+100*21

=7900+2100=10000

30.79+79.70-69.21+31.21

=79.(30+70)-21.(69+31)

=79.100-21.100

=7900-2100

=5800

\(\left(-10+89\right)\cdot2^6+79\left(6^2+21\right)+21^2\)

\(=79\cdot64+79\left(36+21\right)+441\)

\(=79\cdot64+79\cdot57+441\)

\(=79\left(64+57\right)+441\)

\(=79\cdot121+441\)

\(=9559+441\)

\(=10000\)

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

   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 ><

-57

=-100+43

=-57

=-57

  - 2017 . 79 - 2017 . 21

= 2017 . (-79) - 2017 . 21

= 2017 . [ -79 - 21 ]

= 2017 . (-100)

= -201700

Nhớ bấm đúng cho mk nha!

chắc chắn 100%

(-2017).79-2017.21

=2017.(-79-21)

=2017.-100

=-201700

k nha

29 + 11 + 60 + 79 + 21

= 40 + 60 + (79 + 21)

= 100 + 100

= 200

\(29+11+60+79+21\)

\(=\left(79+21\right)+\left(29+11\right)+60\)

\(=100+\left(40+60\right)\)

\(=100+100\)

\(=200\)

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