It's very important to understand the basic difference between adding 2 fractions together and multiplying 2 fractions together.
Take a look at the 2 problems I have written on on the board.
When adding 2 fractions together, we add across the numerators but keep the denominator the same.
So 4/5 + 3/7 is 7/5.
When multiplying 2 fractions together, we multiply across the numerator and we also multiply across the denominators.
So 4/5 · 3/5 is 12/25.
