Add 81/21 and 12/9
1st number: 3 18/21, 2nd number: 1 3/9
81/21 + 12/9 is 109/21.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 9 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 21 × 3 = 63,
81/21 = 81 × 3/21 × 3 = 243/63 - Likewise, for the 2nd fraction, since 9 × 7 = 63,
12/9 = 12 × 7/9 × 7 = 84/63 - Add the two like fractions:
243/63 + 84/63 = 243 + 84/63 = 327/63 - 327/63 simplified gives 109/21
- So, 81/21 + 12/9 = 109/21
In mixed form: 54/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 81/21+24/9 81/42+12/9 81/21+12/18 81/21+36/9 81/63+12/9 81/21+12/27 81/21+60/9 81/21+12/45 81/21+84/9 81/21+12/63