Subtract 3/40 from 81/30
1st number: 2 21/30, 2nd number: 3/40
81/30 - 3/40 is 21/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 40 is 120
Next, find the equivalent fraction of both fractional numbers with denominator 120 - For the 1st fraction, since 30 × 4 = 120,
81/30 = 81 × 4/30 × 4 = 324/120 - Likewise, for the 2nd fraction, since 40 × 3 = 120,
3/40 = 3 × 3/40 × 3 = 9/120 - Subtract the two like fractions:
324/120 - 9/120 = 324 - 9/120 = 315/120 - After reducing the fraction, the answer is 21/8
- In mixed form: 25/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/30-6/40 81/60-3/40 81/30-3/80 81/30-9/40 81/90-3/40 81/30-15/40 81/30-21/40