1. **Problem statement:** A number is increased by 20% and then decreased by 20%. We need to find the net increase or decrease percent. 2. **Formula and rules:** - Increasing a number by 20% means multiplying it by $1 + \frac{20}{100} = 1.2$. - Decreasing a number by 20% means multiplying it by $1 - \frac{20}{100} = 0.8$. - The net effect is the product of these two multipliers. 3. **Calculation:** Let the original number be $x$. After 20% increase: $x \times 1.2 = 1.2x$ After 20% decrease: $1.2x \times 0.8 = 0.96x$ 4. **Interpretation:** The final value is $0.96x$, which is 96% of the original number. 5. **Net change:** Net change = $0.96x - x = -0.04x$ This means a 4% decrease. **Final answer:** The net effect is a 4% decrease.