Problem
FRACTIONS Writing fractions with a common denominator to add or subtract Let's find \( \frac{2}{5}+\frac{1}{3} \) First write the addition with a common denominator. Then add. \[ \frac{2}{5}+\frac{1}{3}=\frac{\square}{\square}+\frac{\square}{\square}=\frac{\square}{\square} \]
Solution
Step 1 ：\[\mathrm{lcm}(5,3) = 15\]
Step 2 ：\[\frac{2}{5}+\frac{1}{3}=\frac{2\times3}{5\times3}+\frac{1\times5}{3\times5}\]
Step 3 ：\[\frac{2}{5}+\frac{1}{3}=\frac{6}{15}+\frac{5}{15}=\frac{11}{15}\]
