Compare 21/84 and 30/90
21/84 is smaller than 30/90
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 90 is 1260
Next, find the equivalent fraction of both fractional numbers with denominator 1260 - For the 1st fraction, since 84 × 15 = 1260,
21/84 = 21 × 15/84 × 15 = 315/1260 - Likewise, for the 2nd fraction, since 90 × 14 = 1260,
30/90 = 30 × 14/90 × 14 = 420/1260 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 315/1260 < 420/1260 or 21/84 < 30/90
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84 and 30/90 21/84 and 60/90 63/84 and 30/90