Subtract 90/81 from 70/20
1st number: 3 10/20, 2nd number: 1 9/81
70/20 - 90/81 is 43/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 81 is 1620
Next, find the equivalent fraction of both fractional numbers with denominator 1620 - For the 1st fraction, since 20 × 81 = 1620,
70/20 = 70 × 81/20 × 81 = 5670/1620 - Likewise, for the 2nd fraction, since 81 × 20 = 1620,
90/81 = 90 × 20/81 × 20 = 1800/1620 - Subtract the two like fractions:
5670/1620 - 1800/1620 = 5670 - 1800/1620 = 3870/1620 - After reducing the fraction, the answer is 43/18
- In mixed form: 27/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 70/40-90/81 70/60-90/81