Evaluate $\frac{7}{9}-\frac{1}{9}$79−19, writing your answer as a simplified fraction.

Evaluate $\frac{5}{13}-\frac{8}{13}$513−813, writing your answer in its simplest form.

Evaluate $-\frac{1}{15}+\frac{7}{15}$−115+715, writing your answer as a simplified fraction.

Evaluate $-\frac{9}{11}+\frac{4}{11}$−911+411, writing your answer in its simplest form.

Simplify numerical expressions involving integers and rational numbers, with and without the use of technology