Subtract 40/84 from 90/21
1st number: 4 6/21, 2nd number: 40/84
90/21 - 40/84 is 80/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
90/21 = 90 × 4/21 × 4 = 360/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
40/84 = 40 × 1/84 × 1 = 40/84 - Subtract the two like fractions:
360/84 - 40/84 = 360 - 40/84 = 320/84 - After reducing the fraction, the answer is 80/21
- In mixed form: 317/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/21-80/84 90/42-40/84 90/63-40/84