Subtract 21/8 from 45/18
1st number: 2 9/18, 2nd number: 2 5/8
45/18 - 21/8 is -1/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 8 is 72
Next, find the equivalent fraction of both fractional numbers with denominator 72 - For the 1st fraction, since 18 × 4 = 72,
45/18 = 45 × 4/18 × 4 = 180/72 - Likewise, for the 2nd fraction, since 8 × 9 = 72,
21/8 = 21 × 9/8 × 9 = 189/72 - Subtract the two like fractions:
180/72 - 189/72 = 180 - 189/72 = -9/72 - After reducing the fraction, the answer is -1/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/18-21/8 45/18-42/8 45/36-21/8 45/18-21/16 45/18-63/8 45/54-21/8 45/18-21/24 45/90-21/8 45/18-21/40 45/18-21/56