Subtract 21/20 from 12/90
1st number: 12/90, 2nd number: 1 1/20
12/90 - 21/20 is -11/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 20 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
12/90 = 12 × 2/90 × 2 = 24/180 - Likewise, for the 2nd fraction, since 20 × 9 = 180,
21/20 = 21 × 9/20 × 9 = 189/180 - Subtract the two like fractions:
24/180 - 189/180 = 24 - 189/180 = -165/180 - After reducing the fraction, the answer is -11/12
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/90-21/20 12/90-42/20 12/90-21/40 36/90-21/20 12/90-63/20 12/90-21/60 60/90-21/20 84/90-21/20