Compare 21/81 and 20/18
1st number: 21/81, 2nd number: 1 2/18
21/81 is smaller than 20/18
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 18 is 162
Next, find the equivalent fraction of both fractional numbers with denominator 162 - For the 1st fraction, since 81 × 2 = 162,
21/81 = 21 × 2/81 × 2 = 42/162 - Likewise, for the 2nd fraction, since 18 × 9 = 162,
20/18 = 20 × 9/18 × 9 = 180/162 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 42/162 < 180/162 or 21/81 < 20/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/81 and 20/18 21/81 and 40/18 21/81 and 20/36 63/81 and 20/18 21/81 and 60/18 21/81 and 20/54 21/81 and 20/90