Question

Bài 5 : Tính nhanh  

a, 10000 - 47 * 72 - 47 * 28

b, 3457 - 27  *48  - 48 * 73 + 6543

Answer 1

a) 10000 - 47 . 72 - 47 . 28

= 10000 - 47 ( 72 - 28 )

= 10000 - 47 . 44

= 10000 - 2068

= 7932

b) 3457 - 27 . 48 - 48 . 73 + 6543

= 3457 - 48 ( - 27 - 48 ) + 6543

= 3457 - 48 . ( - 75 ) + 6543

= 3457 - ( - 27 ) + 6543

= 3457 + 27 + 6543

= 10027

Answer 2

a, 10000-47×72-47×28

= 10000-47(72+28)

=10000-47×100

=10000-4700= 5300