Subtract 84/40 from 72/21
1st number: 3 9/21, 2nd number: 2 4/40
72/21 - 84/40 is 93/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
72/21 = 72 × 40/21 × 40 = 2880/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
84/40 = 84 × 21/40 × 21 = 1764/840 - Subtract the two like fractions:
2880/840 - 1764/840 = 2880 - 1764/840 = 1116/840 - After reducing the fraction, the answer is 93/70
- In mixed form: 123/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/42-84/40 72/21-84/80 72/63-84/40