Subtract 42/16 from 21/81
1st number: 21/81, 2nd number: 2 10/16
21/81 - 42/16 is -511/216.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 16 is 1296
Next, find the equivalent fraction of both fractional numbers with denominator 1296 - For the 1st fraction, since 81 × 16 = 1296,
21/81 = 21 × 16/81 × 16 = 336/1296 - Likewise, for the 2nd fraction, since 16 × 81 = 1296,
42/16 = 42 × 81/16 × 81 = 3402/1296 - Subtract the two like fractions:
336/1296 - 3402/1296 = 336 - 3402/1296 = -3066/1296 - After reducing the fraction, the answer is -511/216
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/81-42/16 21/81-84/16 21/81-42/32 63/81-42/16 21/81-42/48 21/81-42/80