Compare 3/21 and 15/45
3/21 is smaller than 15/45
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
3/21 = 3 × 15/21 × 15 = 45/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
15/45 = 15 × 7/45 × 7 = 105/315 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 45/315 < 105/315 or 3/21 < 15/45
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/21 and 15/45 3/21 and 30/45 3/42 and 15/45 3/21 and 15/90 9/21 and 15/45 3/63 and 15/45 15/21 and 15/45 3/21 and 75/45