Question

Martha buys a ribbon that is 7/10 of a yard long.

She cuts off 2/5 of a yard.
How many yards of ribbon does Martha have left?

Answer 1

7/10 - 2/5 = 7/10 - 4/10 = 3/10

Explanation:

Equalize both denominators, as in 2/5 = 4/10.