Step 1: Identify the number of decimal places

The decimal 21 has 0 decimal places.

Step 2: Multiply by the appropriate power of 10

Multiply by 10⁰ = 1 to eliminate the decimal point.

21 × 1 = 21

Step 3: Write as a fraction

Step 4: Simplify the fraction

Find the greatest common divisor (GCD) of 21 and 1.

GCD(21, 1) = 1

Divide both the numerator and denominator by the GCD: