1. **State the problem:** Calculate $\frac{2}{5} - \frac{3}{10}$. 2. **Find a common denominator:** The denominators are 5 and 10. The least common denominator (LCD) is 10. 3. **Convert fractions:** Convert $\frac{2}{5}$ to have denominator 10: $$\frac{2}{5} = \frac{2 \times 2}{5 \times 2} = \frac{4}{10}$$ 4. **Subtract the fractions:** $$\frac{4}{10} - \frac{3}{10} = \frac{4 - 3}{10} = \frac{1}{10}$$ 5. **Final answer:** The result of $\frac{2}{5} - \frac{3}{10}$ is $\frac{1}{10}$.