Subtract 20/9 from 40/21
1st number: 1 19/21, 2nd number: 2 2/9
40/21 - 20/9 is -20/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
40/21 = 40 × 3/21 × 3 = 120/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
20/9 = 20 × 7/9 × 7 = 140/63 - Subtract the two like fractions:
120/63 - 140/63 = 120 - 140/63 = -20/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/21-20/9 40/21-40/9 40/42-20/9 40/21-20/18 40/21-60/9 40/63-20/9 40/21-20/27 40/21-20/45 40/21-20/63