Subtract 81/84 from 7/90
7/90 - 81/84 is -1117/1260.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 84 is 1260
Next, find the equivalent fraction of both fractional numbers with denominator 1260 - For the 1st fraction, since 90 × 14 = 1260,
7/90 = 7 × 14/90 × 14 = 98/1260 - Likewise, for the 2nd fraction, since 84 × 15 = 1260,
81/84 = 81 × 15/84 × 15 = 1215/1260 - Subtract the two like fractions:
98/1260 - 1215/1260 = 98 - 1215/1260 = -1117/1260
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 14/90-81/84 21/90-81/84 35/90-81/84 49/90-81/84