Compare 9/21 and 20/45
9/21 is smaller than 20/45
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,
9/21 = 9 × 15/21 × 15 = 135/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
20/45 = 20 × 7/45 × 7 = 140/315 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 135/315 < 140/315 or 9/21 < 20/45
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/21 and 20/45 9/21 and 40/45 9/42 and 20/45 9/21 and 20/90 27/21 and 20/45 9/21 and 60/45 9/63 and 20/45 45/21 and 20/45 63/21 and 20/45