1. **State the problem:** Find 15% of 20. 2. **Formula:** To find a percentage of a number, use the formula: $$\text{Percentage of a number} = \frac{\text{percent}}{100} \times \text{number}$$ 3. **Apply the formula:** Here, percent = 15 and number = 20. $$15\% \text{ of } 20 = \frac{15}{100} \times 20$$ 4. **Calculate:** $$= \frac{15}{100} \times 20 = \frac{15 \times 20}{100}$$ 5. **Simplify:** $$= \frac{300}{100}$$ 6. **Divide numerator and denominator by 100:** $$= \frac{\cancel{300}^{3} \times 100}{\cancel{100}} = 3$$ 7. **Final answer:** 15% of 20 is **3**. This means if you take 15 parts out of 100 parts of 20, you get 3.