Subtract 72/21 from 18/5
1st number: 3 3/5, 2nd number: 3 9/21
18/5 - 72/21 is 6/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 5 × 21 = 105,
18/5 = 18 × 21/5 × 21 = 378/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
72/21 = 72 × 5/21 × 5 = 360/105 - Subtract the two like fractions:
378/105 - 360/105 = 378 - 360/105 = 18/105 - After reducing the fraction, the answer is 6/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/5-72/21 18/10-72/21 18/5-72/42 54/5-72/21 18/15-72/21 18/5-72/63 90/5-72/21 18/25-72/21 18/35-72/21