-Write the decimal as a fraction, leaving 1 as the denominator

-Multiply both, the numerator and denominator, by 10 (or 100)

-Reduce the fraction

Example: 0.75

1. Let the decimal be the numerator and 1 as the denominator

 frac{0.75}{1}

2. Since there are two digits after the decimal point, multiply both by 100

 frac{0.75 * 100}{1 * 100} =  frac{75}{100}

3. Reduce

 frac{75 / 5}{100 / 5} =  frac{15}{20}

 frac{15}{20} =  frac{3}{4}

0.75, written as a fraction, is 3/4.