Subtract 7/90 from 42/72
42/72 - 7/90 is 91/180.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 90 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
42/72 = 42 × 5/72 × 5 = 210/360 - Likewise, for the 2nd fraction, since 90 × 4 = 360,
7/90 = 7 × 4/90 × 4 = 28/360 - Subtract the two like fractions:
210/360 - 28/360 = 210 - 28/360 = 182/360 - After reducing the fraction, the answer is 91/180
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/72-7/90 42/72-14/90 42/72-21/90 42/72-35/90 42/72-49/90