Grade 4 - Lesson 15 Practice Problems

$$\frac{1}{4}$$

$$\frac{3}{4}$$

$$\frac{1}{8}$$

$$\frac{3}{8}$$

$$\frac{5}{7}$$ $$+$$ $$\frac{3}{7}$$

$$\frac{8}{7\ }$$ $$+$$ $$\frac{3}{7}$$

$$\frac{7}{7}$$ $$-$$ $$\frac{2}{7}$$

$$\frac{8}{7}$$ $$-$$ $$\frac{3}{7}$$

There is no mistake. He is correct.

He should have added the denominators to get $$\frac{6}{16}$$

He added correctly, but one pizza was a large size and one was a small size so we can't add the two fractions together because the pieces will not be the same size. The large pizza will have bigger slices than the small pizza. In order to add fractions, the pizza's would have to be the same size.