Subtract 5/81 from 21/8
1st number: 2 5/8, 2nd number: 5/81
21/8 - 5/81 is 1661/648.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 81 is 648
Next, find the equivalent fraction of both fractional numbers with denominator 648 - For the 1st fraction, since 8 × 81 = 648,
21/8 = 21 × 81/8 × 81 = 1701/648 - Likewise, for the 2nd fraction, since 81 × 8 = 648,
5/81 = 5 × 8/81 × 8 = 40/648 - Subtract the two like fractions:
1701/648 - 40/648 = 1701 - 40/648 = 1661/648 - In mixed form: 2365/648
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/8-5/81 21/8-10/81 21/16-5/81 63/8-5/81 21/8-15/81 21/24-5/81 21/8-25/81 21/40-5/81 21/8-35/81 21/56-5/81