Subtract 72/21 from 45/3
1st number: 15 0/3, 2nd number: 3 9/21
45/3 - 72/21 is 81/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 3 and 21 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 3 × 7 = 21,
45/3 = 45 × 7/3 × 7 = 315/21 - Likewise, for the 2nd fraction, since 21 × 1 = 21,
72/21 = 72 × 1/21 × 1 = 72/21 - Subtract the two like fractions:
315/21 - 72/21 = 315 - 72/21 = 243/21 - After reducing the fraction, the answer is 81/7
- In mixed form: 114/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/3-72/21 45/6-72/21 45/3-72/42 45/9-72/21 45/3-72/63 45/15-72/21 45/21-72/21