Express 4.05 in Different Mathematical Forms: Decimal Conversion Practice

Count the decimal places! For 0.05, there are 2 decimal places, so use 100 as the denominator. For 0.5, use 10. For 0.125, use 1000.

Start by dividing both numerator and denominator by small numbers like 2, 3, or 5. For $\frac{5}{100}$, both divide by 5 to get $\frac{1}{20}$.

Yes! $4\frac{1}{20} = \frac{81}{20}$, but mixed numbers are usually preferred for decimals like 4.05 since they clearly show the whole and fractional parts.

Convert back to decimal: divide the fraction part and add to the whole number. $\frac{1}{20} = 0.05$, so $4 + 0.05 = 4.05$ ✓

This comes from not simplifying correctly. If you wrote 0.05 as $\frac{5}{100}$ but then divided by 25 instead of 5, you'd get $\frac{1}{200}$, which equals 0.005, not 0.05!