Subtract 54/70 from 21/28
21/28 - 54/70 is -3/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 70 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 28 × 5 = 140,
21/28 = 21 × 5/28 × 5 = 105/140 - Likewise, for the 2nd fraction, since 70 × 2 = 140,
54/70 = 54 × 2/70 × 2 = 108/140 - Subtract the two like fractions:
105/140 - 108/140 = 105 - 108/140 = -3/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/28-54/70 21/56-54/70 63/28-54/70 21/84-54/70