Compare 90/72 and 81/21
1st number: 1 18/72, 2nd number: 3 18/21
90/72 is smaller than 81/21
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
90/72 = 90 × 7/72 × 7 = 630/504 - Likewise, for the 2nd fraction, since 21 × 24 = 504,
81/21 = 81 × 24/21 × 24 = 1944/504 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 630/504 < 1944/504 or 90/72 < 81/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/72 and 81/42 90/72 and 81/63