[tex]1 \frac{3}{14} + 2 \frac{1}{7} \\ \\ 3 + \frac{3}{14} + \frac{1}{7} \\ \\ LCD = 14 \\ \\ 3 + \frac{3}{14} + \frac{1 \times 2}{7 \times 2} \\ \\ 3 + \frac{3}{14} + \frac{2}{14} \\ \\ 3 + \frac{3 + 2}{14} \\ \\ 3 \frac{5}{14} \\ \\ Answer: \fbox {3 5/14} \ or \ \fbox {3.3571} [/tex]