A number is increased by 25%. By what percentage must the new number be decreased to get back the original number?

Fractions, decimals, and percentages are three notations for the same idea. Convert freely:

- **Fraction → percentage**: multiply by 100. $\frac{3}{5}=\frac{3}{5}\times 100\%=60\%$.
- **Percentage → fraction**: divide by 100 and simplify. $75\%=\frac{75}{100}=\frac{3}{4}$.
- **Decimal → percentage**: shift two places right. 0.34 = 34%.
- **Percentage → decimal**: shift two places left. 8% = 0.08.

With practice, this becomes automatic and you can move between forms without thinking.