Subtract 28/45 from 12/21
12/21 - 28/45 is -16/315.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
12/21 = 12 × 15/21 × 15 = 180/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
28/45 = 28 × 7/45 × 7 = 196/315 - Subtract the two like fractions:
180/315 - 196/315 = 180 - 196/315 = -16/315
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-28/45 12/21-56/45 12/42-28/45 12/21-28/90 36/21-28/45 12/21-84/45 12/63-28/45 60/21-28/45 84/21-28/45