Subtract 18/84 from 30/21
1st number: 1 9/21, 2nd number: 18/84
30/21 - 18/84 is 17/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
30/21 = 30 × 4/21 × 4 = 120/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
18/84 = 18 × 1/84 × 1 = 18/84 - Subtract the two like fractions:
120/84 - 18/84 = 120 - 18/84 = 102/84 - After reducing the fraction, the answer is 17/14
- In mixed form: 13/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21-18/84 30/21-36/84 30/42-18/84 90/21-18/84 30/21-54/84 30/63-18/84 30/21-90/84