Question

Tính bằng cách thuận tiện.

a) 524 × 63 + 524 × 37 – 2 400                           b) \(\dfrac{7}{9}\times\dfrac{6}{5}+\dfrac{6}{5}\times\dfrac{2}{9}+\dfrac{4}{5}\)

Answer 1

`a, 524 xx 63 + 524 xx 37 - 2400`

`= 524 xx (63+37)-2400`

`= 524xx100-2400`

`= 52400-2400`

`= 50000`

`b, 7/9 xx 6/5 + 6/5 xx2/9 + 4/5`

`= 6/5xx(7/9+2/9)+4/5`

`= 6/5xx1+4/5`

`= 10/5`

`=2`