Compare 21/80 and 20/70
21/80 is smaller than 20/70
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 70 is 560
Next, find the equivalent fraction of both fractional numbers with denominator 560 - For the 1st fraction, since 80 × 7 = 560,
21/80 = 21 × 7/80 × 7 = 147/560 - Likewise, for the 2nd fraction, since 70 × 8 = 560,
20/70 = 20 × 8/70 × 8 = 160/560 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 147/560 < 160/560 or 21/80 < 20/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/80 and 20/70 21/80 and 40/70 63/80 and 20/70 21/80 and 60/70