Subtract 21/12 from 20/80
1st number: 20/80, 2nd number: 1 9/12
20/80 - 21/12 is -3/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 12 is 240
Next, find the equivalent fraction of both fractional numbers with denominator 240 - For the 1st fraction, since 80 × 3 = 240,
20/80 = 20 × 3/80 × 3 = 60/240 - Likewise, for the 2nd fraction, since 12 × 20 = 240,
21/12 = 21 × 20/12 × 20 = 420/240 - Subtract the two like fractions:
60/240 - 420/240 = 60 - 420/240 = -360/240 - After reducing the fraction, the answer is -3/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/80-21/12 20/80-42/12 20/80-21/24 60/80-21/12 20/80-63/12 20/80-21/36 20/80-21/60 20/80-21/84