Add 21/12 and 28/21
1st number: 1 9/12, 2nd number: 1 7/21
21/12 + 28/21 is 37/12.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 12 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 12 × 7 = 84,
21/12 = 21 × 7/12 × 7 = 147/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
28/21 = 28 × 4/21 × 4 = 112/84 - Add the two like fractions:
147/84 + 112/84 = 147 + 112/84 = 259/84 - 259/84 simplified gives 37/12
- So, 21/12 + 28/21 = 37/12
In mixed form: 31/12
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