Subtract 18/90 from 21/7
1st number: 3 0/7, 2nd number: 18/90
21/7 - 18/90 is 14/5.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 7 × 90 = 630,
21/7 = 21 × 90/7 × 90 = 1890/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
18/90 = 18 × 7/90 × 7 = 126/630 - Subtract the two like fractions:
1890/630 - 126/630 = 1890 - 126/630 = 1764/630 - After reducing the fraction, the answer is 14/5
- In mixed form: 24/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/7-18/90 21/7-36/90 21/14-18/90 63/7-18/90 21/7-54/90 21/35-18/90 21/49-18/90