Subtract 18/20 from 21/36
21/36 - 18/20 is -19/60.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 36 and 20 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 36 × 5 = 180,
21/36 = 21 × 5/36 × 5 = 105/180 - Likewise, for the 2nd fraction, since 20 × 9 = 180,
18/20 = 18 × 9/20 × 9 = 162/180 - Subtract the two like fractions:
105/180 - 162/180 = 105 - 162/180 = -57/180 - After reducing the fraction, the answer is -19/60
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/36-18/20 21/36-36/20 21/72-18/20 21/36-18/40 63/36-18/20 21/36-54/20 21/36-18/60 21/36-90/20