1. The problem is to calculate $28 \times \frac{1}{100}$.\n\n2. The formula used here is multiplication of a number by a fraction: $a \times \frac{b}{c} = \frac{a \times b}{c}$.\n\n3. Applying the formula: $28 \times \frac{1}{100} = \frac{28 \times 1}{100} = \frac{28}{100}$.\n\n4. Simplify the fraction $\frac{28}{100}$ by dividing numerator and denominator by their greatest common divisor, which is 4: $\frac{28 \div 4}{100 \div 4} = \frac{7}{25}$.\n\n5. To express as a decimal, divide 7 by 25: $7 \div 25 = 0.28$.\n\n6. Therefore, $28 \times \frac{1}{100} = 0.28$.