Subtract 21/12 from 28/90
1st number: 28/90, 2nd number: 1 9/12
28/90 - 21/12 is -259/180.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 12 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
28/90 = 28 × 2/90 × 2 = 56/180 - Likewise, for the 2nd fraction, since 12 × 15 = 180,
21/12 = 21 × 15/12 × 15 = 315/180 - Subtract the two like fractions:
56/180 - 315/180 = 56 - 315/180 = -259/180
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/90-21/12 28/90-42/12 28/90-21/24 84/90-21/12 28/90-63/12 28/90-21/36 28/90-21/60 28/90-21/84