Subtract 70/20 from 21/84
1st number: 21/84, 2nd number: 3 10/20
21/84 - 70/20 is -13/4.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 84 × 5 = 420,
21/84 = 21 × 5/84 × 5 = 105/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
70/20 = 70 × 21/20 × 21 = 1470/420 - Subtract the two like fractions:
105/420 - 1470/420 = 105 - 1470/420 = -1365/420 - After reducing the fraction, the answer is -13/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84-70/20 21/84-70/40 63/84-70/20 21/84-70/60