Subtract 42/45 from 4/21
4/21 - 42/45 is -26/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
4/21 = 4 × 15/21 × 15 = 60/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
42/45 = 42 × 7/45 × 7 = 294/315 - Subtract the two like fractions:
60/315 - 294/315 = 60 - 294/315 = -234/315 - After reducing the fraction, the answer is -26/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/21-42/45 4/21-84/45 4/42-42/45 4/21-42/90 12/21-42/45 4/63-42/45 20/21-42/45 28/21-42/45