1. The problem is to add the fractions $\frac{1}{7}$ and $\frac{2}{7}$. 2. When adding fractions with the same denominator, you add the numerators and keep the denominator the same. The formula is: $$\frac{a}{c} + \frac{b}{c} = \frac{a+b}{c}$$ 3. Here, $a=1$, $b=2$, and $c=7$. So, $$\frac{1}{7} + \frac{2}{7} = \frac{1+2}{7} = \frac{3}{7}$$ 4. The sum of $\frac{1}{7}$ and $\frac{2}{7}$ is $\frac{3}{7}$.