Subtract 18/21 from 90/5
1st number: 18 0/5, 2nd number: 18/21
90/5 - 18/21 is 120/7.
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,
90/5 = 90 × 21/5 × 21 = 1890/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
18/21 = 18 × 5/21 × 5 = 90/105 - Subtract the two like fractions:
1890/105 - 90/105 = 1890 - 90/105 = 1800/105 - After reducing the fraction, the answer is 120/7
- In mixed form: 171/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/5-36/21 90/10-18/21 90/5-18/42 90/5-54/21 90/15-18/21 90/5-18/63 90/5-90/21 90/25-18/21 90/35-18/21