1. The problem is to convert the mixed number percentage $2 \frac{1}{2}\%$ into a decimal or fraction. 2. Recall that a percentage means "per hundred," so $x\% = \frac{x}{100}$. 3. First, convert the mixed number $2 \frac{1}{2}$ to an improper fraction: $$2 \frac{1}{2} = \frac{2 \times 2 + 1}{2} = \frac{5}{2}$$ 4. Now express the percentage as a fraction: $$2 \frac{1}{2}\% = \frac{5}{2}\% = \frac{5}{2} \times \frac{1}{100} = \frac{5}{2} \times \frac{1}{100}$$ 5. Multiply the fractions: $$\frac{5}{2} \times \frac{1}{100} = \frac{5 \times 1}{2 \times 100} = \frac{5}{200}$$ 6. Simplify the fraction by dividing numerator and denominator by 5: $$\frac{\cancel{5}}{\cancel{200}} = \frac{1}{40}$$ 7. Therefore, $2 \frac{1}{2}\%$ as a decimal is: $$\frac{1}{40} = 0.025$$ Final answer: $2 \frac{1}{2}\% = \frac{1}{40} = 0.025$