Question

Tính nhanh:

1/7 x 1/5 + 1/7 x 2/5 + 1/5 x 4/7

Answer 1

1/7 x 1/5 + 1/7 x 2/5 + 1/5 x 4/7

= 1/7 x 1/5 + 1/7 x 2/5 + 4/5 x 1/7

= 1/7 x (1/5 + 2/5 + 4/5)

= 1/7 x 7/5

= 1/5

Answer 2

Đáp số bằng \(\frac{1}{5}\)

Answer 3

1/7 x 1/5 + 1/7 x 2/5 + 1/5 x 4/7

= 1/7 x 1/5 + 1/7 x 2/5 + 4/5 x 1/7

= 1/7 x (1/5 + 2/5 + 4/5)

= 1/7 x 7/5

= 1/5

Answer 4

1/7 x 1/5 + 1/7 x 2/5 + 1/5 x 4/7

= 1/7 x 1/5 + 1/7 x 2/5 + 1/7 x 4/5

= 1/7 x ( 1/5 + 2/5 + 4/5 )

= 1/7 x 7/5

= 1/5