can someone please help me solve the following problems

Solve the following:

1. 2/7 - 1/3 = ?

2. 4/5 x 15/2 = ?

3. 2 1/2 ÷ 3/4 = ?

1. Find the common denominator.

2/7 - 1/3 = ?
6/21 - 7/21 = -1/21

2. Multiply the numerators and then multiply the denominators.

3. Invert the divisor and then multiply.

We'll be glad to check your answers.