Subtract 90/5 from 21/8
1st number: 2 5/8, 2nd number: 18 0/5
21/8 - 90/5 is -123/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 5 is 40
Next, find the equivalent fraction of both fractional numbers with denominator 40 - For the 1st fraction, since 8 × 5 = 40,
21/8 = 21 × 5/8 × 5 = 105/40 - Likewise, for the 2nd fraction, since 5 × 8 = 40,
90/5 = 90 × 8/5 × 8 = 720/40 - Subtract the two like fractions:
105/40 - 720/40 = 105 - 720/40 = -615/40 - After reducing the fraction, the answer is -123/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/8-90/5 21/16-90/5 21/8-90/10 63/8-90/5 21/24-90/5 21/8-90/15 21/40-90/5 21/8-90/25 21/56-90/5 21/8-90/35