Question

Tính nhanh

a)215*86+13*215+215

b)53*128-41*128-128-128

Answer 1

a)

Ta có 215 x 86 +13 x 215 +215

=215x(86+13+1)

=215 x 100

=215

b)

Ta có 52 x 128 - 41 x 128 - 128 -128

=128 x ( 52 -41 -1-1)

=128 x  9

=1152

Answer 2

a)   215*86 + 13*215 + 215 = 215*( 86 + 13 + 1 ) = 215*100 = 21500

b)   53*128 - 41*128 - 128 - 128 = ( 53 - 41 - 1 - 1 )*128 = 10*128 = 1280

Answer 3

a) 215*86+13*215+215

=215*(86+13+1)

=215*100

=21500

b) 53*128-41*128-128-128

=128*(53-41-1-1)

=128*10

=1280

Answer 4

a) 215 x 86 + 13 x 215 + 215

= 215 x ( 86 + 13 + 1 ) 

= 215 x 100

= 21500

b) 53 x 128 - 41 x 128 - 128 - 128

= 128 x ( 53 - 41 - 1 - 1 )

= 128 x 10

= 1280

Answer 5

a]21500    b]1280