1. **State the problem:** Calculate $\frac{1}{2} \times 4$. 2. **Formula used:** Multiplying a fraction by a whole number is done by multiplying the numerator by the whole number and keeping the denominator the same. 3. **Intermediate work:** $$\frac{1}{2} \times 4 = \frac{1 \times 4}{2} = \frac{4}{2}$$ 4. **Simplify the fraction:** $$\frac{\cancel{4}}{\cancel{2}} = 2$$ 5. **Explanation:** Multiplying $\frac{1}{2}$ by 4 means taking half of 4, which is 2. **Final answer:** $2$