Subtract 1/21 from 45/72
45/72 - 1/21 is 97/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
45/72 = 45 × 7/72 × 7 = 315/504 - Likewise, for the 2nd fraction, since 21 × 24 = 504,
1/21 = 1 × 24/21 × 24 = 24/504 - Subtract the two like fractions:
315/504 - 24/504 = 315 - 24/504 = 291/504 - After reducing the fraction, the answer is 97/168
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/72-1/21 45/72-2/21 45/72-1/42 45/72-3/21 45/72-1/63 45/72-5/21 45/72-7/21