Question

28 . ( 231 + 69 ) + 72 . ( 231 + 69 )

tính nhanh

 

Answer 1

   28  .  ( 231  +  69 )  +  72  .  ( 231  +  69 )

= ( 231  +  69 )  .  ( 72  +  28 )

= 300  .  100

= 30000

Answer 2

=28.231+28.69+72.231+72.69

=28.231+72.231+28.69+72.69

=231.(72+28)+69.(28+72)

=231.100+69.100

=32100+6900

=39000

Answer 3

28+72.(213+69)=100.282=28200