Subtract 90/5 from 21/84
1st number: 21/84, 2nd number: 18 0/5
21/84 - 90/5 is -71/4.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 5 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 5 × 84 = 420,
90/5 = 90 × 84/5 × 84 = 7560/420 - Subtract the two like fractions:
105/420 - 7560/420 = 105 - 7560/420 = -7455/420 - After reducing the fraction, the answer is -71/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84-90/5 21/84-90/10 63/84-90/5 21/84-90/15 21/84-90/25 21/84-90/35