Subtract 90/21 from 20/10
1st number: 2 0/10, 2nd number: 4 6/21
20/10 - 90/21 is -16/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 10 and 21 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 10 × 21 = 210,
20/10 = 20 × 21/10 × 21 = 420/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
90/21 = 90 × 10/21 × 10 = 900/210 - Subtract the two like fractions:
420/210 - 900/210 = 420 - 900/210 = -480/210 - After reducing the fraction, the answer is -16/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/10-90/21 20/10-90/42 60/10-90/21 20/30-90/21 20/10-90/63 20/50-90/21 20/70-90/21