Subtract 42/9 from 21/8
1st number: 2 5/8, 2nd number: 4 6/9
21/8 - 42/9 is -49/24.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 9 is 72
Next, find the equivalent fraction of both fractional numbers with denominator 72 - For the 1st fraction, since 8 × 9 = 72,
21/8 = 21 × 9/8 × 9 = 189/72 - Likewise, for the 2nd fraction, since 9 × 8 = 72,
42/9 = 42 × 8/9 × 8 = 336/72 - Subtract the two like fractions:
189/72 - 336/72 = 189 - 336/72 = -147/72 - After reducing the fraction, the answer is -49/24
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/8-42/9 21/8-84/9 21/16-42/9 21/8-42/18 63/8-42/9 21/24-42/9 21/8-42/27 21/40-42/9 21/8-42/45 21/56-42/9 21/8-42/63