Add 21/40 and 16/81
21/40 + 16/81 is 2341/3240.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 81 is 3240
Next, find the equivalent fraction of both fractional numbers with denominator 3240 - For the 1st fraction, since 40 × 81 = 3240,
21/40 = 21 × 81/40 × 81 = 1701/3240 - Likewise, for the 2nd fraction, since 81 × 40 = 3240,
16/81 = 16 × 40/81 × 40 = 640/3240 - Add the two like fractions:
1701/3240 + 640/3240 = 1701 + 640/3240 = 2341/3240 - So, 21/40 + 16/81 = 2341/3240
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40+16/81 21/40+32/81 21/80+16/81 63/40+16/81 21/40+48/81 21/40+80/81