Subtract 8/7 from 21/45
1st number: 21/45, 2nd number: 1 1/7
21/45 - 8/7 is -71/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 7 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 45 × 7 = 315,
21/45 = 21 × 7/45 × 7 = 147/315 - Likewise, for the 2nd fraction, since 7 × 45 = 315,
8/7 = 8 × 45/7 × 45 = 360/315 - Subtract the two like fractions:
147/315 - 360/315 = 147 - 360/315 = -213/315 - After reducing the fraction, the answer is -71/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/45-8/7 21/45-16/7 21/90-8/7 21/45-8/14 63/45-8/7 21/45-24/7 21/45-8/21 21/45-40/7 21/45-8/35 21/45-56/7 21/45-8/49