Subtract 1/4 from 21/90
21/90 - 1/4 is -1/60.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 4 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
21/90 = 21 × 2/90 × 2 = 42/180 - Likewise, for the 2nd fraction, since 4 × 45 = 180,
1/4 = 1 × 45/4 × 45 = 45/180 - Subtract the two like fractions:
42/180 - 45/180 = 42 - 45/180 = -3/180 - After reducing the fraction, the answer is -1/60
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/90-1/4 21/90-2/4 21/90-1/8 63/90-1/4 21/90-3/4 21/90-1/12 21/90-5/4 21/90-1/20 21/90-7/4 21/90-1/28