Compare 12/21 and 30/40
12/21 is smaller than 30/40
Steps for comparing fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
12/21 = 12 × 40/21 × 40 = 480/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
30/40 = 30 × 21/40 × 21 = 630/840 - Since the denominators are now the same, the fraction with the bigger numerator is the greater fraction
- 480/840 < 630/840 or 12/21 < 30/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21 and 30/40 12/21 and 60/40 12/42 and 30/40 12/21 and 30/80 36/21 and 30/40 12/21 and 90/40 12/63 and 30/40 60/21 and 30/40 84/21 and 30/40