a: =100+100=100

b: =1+2=3

a) 48,25 + 12,72 + 51,75 + 87,28
  = (48,25 + 51,75) + (12,72 + 87,28)
  = 100 + 100
  = 200
b) 0,087 + 1,123 + 0,913 + 0,877
  = ( 0,087 + 0,913) + ( 1,123 + 0,877)
  = 1 + 2
  = 3

a =200

b = 3

\(\dfrac{1}{3}+\dfrac{6}{5}-\dfrac{1}{5}+\dfrac{2}{3}=2\)

1/3+6/5−1/5+2/3=2

2,5 x 12 ,5 x 8 x 0,4=(2,5 x 0,4 ) x(12,5 x8)

                            =1x100=100

=2,5 x 12,5 x 8 x 0,4

=(2,5 x 0,4) x (12,5 x 8)

=1 x 100

=100

Tính bằng cách thuận tiện nhất: 2,5x12,5x8x0,4=100

k mik nha

1212/1515 = 1212 :1515 

= 12 x 101 : 15 x 101 

= 12/15

dinh hoang vu

\(\frac{1212}{1515}=\frac{1212\div101}{1515\div101}\)

\(=\frac{12}{15}=\frac{4}{5}\)

\(\frac{1212}{1515}=\frac{2^2.3.101}{3.5.101}=\frac{2^2}{5}=\frac{4}{5}\)

  25x20x125x8-8x20x5x125

=(25x8)x(20x125)-(20x5)x(8x125)

=200x2500-100x1000

=500000-100000=400000

mk tính giống bạn kia

giai giup minh nha

476x72+476x28

=476x(72+28)

=476x100

=47 600

476x72+476x28

=476x(72+28)

=476x100

=47 600

54x342-44x342

=342x(54-44)

=342x10

=3 420

54x342-44x342

=342x(54-44)

=342x10

=3 420

54x342-44x342

=342x(54-44)

=342x10

=3 420

= 46,5+(16,8-0,8)= 46,5+ 16= 62,5