Subtract 21/7 from 28/45
1st number: 28/45, 2nd number: 3 0/7
28/45 - 21/7 is -107/45.
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,
28/45 = 28 × 7/45 × 7 = 196/315 - Likewise, for the 2nd fraction, since 7 × 45 = 315,
21/7 = 21 × 45/7 × 45 = 945/315 - Subtract the two like fractions:
196/315 - 945/315 = 196 - 945/315 = -749/315 - After reducing the fraction, the answer is -107/45
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/45-21/7 28/45-42/7 28/90-21/7 28/45-21/14 84/45-21/7 28/45-63/7 28/45-21/35 28/45-21/49