Compare 15/42 and 18/21
15/42 is smaller than 18/21
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,
15/42 = 15 × 1/42 × 1 = 15/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
18/21 = 18 × 2/21 × 2 = 36/42 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 15/42 < 36/42 or 15/42 < 18/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/42 and 18/21 15/42 and 36/21 15/84 and 18/21 15/42 and 18/42 45/42 and 18/21 15/42 and 54/21 15/42 and 18/63 75/42 and 18/21 15/42 and 90/21