To solve the expression $\frac{3}{8} + \frac{2}{5}$, we need to add the two fractions. Here's the process:

1. Find a common denominator: The denominators are 8 and 5. The least common denominator (LCD) is 40.

2. Convert each fraction: $\frac{3}{8} = \frac{3 \times 5}{8 \times 5} = \frac{15}{40}$ $\frac{2}{5} = \frac{2 \times 8}{5 \times 8} = \frac{16}{40}$

3. Add the numerators: $\frac{15}{40} + \frac{16}{40} = \frac{15 + 16}{40} = \frac{31}{40}$

Thus, $\frac{3}{8} + \frac{2}{5} = \frac{31}{40}$.

Would you like more details or have any questions?

Here are 5 related questions:

1. How do you subtract fractions with different denominators?
2. What is the least common denominator, and how do you find it?
3. Can you convert $\frac{31}{40}$ to a decimal?
4. How do you multiply or divide fractions?
5. What is the process for simplifying fractions?

Tip: Always simplify your answer if possible, but in this case, $\frac{31}{40}$ is already in its simplest form.