Compare 18/15 and 30/21
1st number: 1 3/15, 2nd number: 1 9/21
18/15 is smaller than 30/21
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
18/15 = 18 × 7/15 × 7 = 126/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
30/21 = 30 × 5/21 × 5 = 150/105 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 126/105 < 150/105 or 18/15 < 30/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/15 and 30/21 18/15 and 60/21 18/30 and 30/21 18/15 and 30/42 54/15 and 30/21 18/15 and 90/21 18/45 and 30/21 18/15 and 30/63 90/15 and 30/21 18/75 and 30/21