Compare 21/42 and 15/21
21/42 is smaller than 15/21
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
21/42 = 21 × 1/42 × 1 = 21/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
15/21 = 15 × 2/21 × 2 = 30/42 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 21/42 < 30/42 or 21/42 < 15/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42 and 30/21 21/84 and 15/21 21/42 and 15/42 63/42 and 15/21 21/42 and 45/21 21/42 and 15/63 21/42 and 75/21