Add 12/21 and 21/84
12/21 + 21/84 is 23/28.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 84 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
12/21 = 12 × 4/21 × 4 = 48/84 - Likewise, for the 2nd fraction, since 84 × 1 = 84,
21/84 = 21 × 1/84 × 1 = 21/84 - Add the two like fractions:
48/84 + 21/84 = 48 + 21/84 = 69/84 - 69/84 simplified gives 23/28
- So, 12/21 + 21/84 = 23/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21+21/84 12/21+42/84 12/42+21/84 36/21+21/84 12/21+63/84 12/63+21/84 60/21+21/84 84/21+21/84