Add 81/12 and 21/7, Solve 6 9/12 + 3 0/7 as a fraction

Add 81/12 and 21/7

1^st number: 6 9/12, 2^nd number: 3 0/7

81/12 + 21/7 is 39/4.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 7 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 12 × 7 = 84,
81/12 = 81 × 7/12 × 7 = 567/84
Likewise, for the 2nd fraction, since 7 × 12 = 84,
21/7 = 21 × 12/7 × 12 = 252/84
Add the two like fractions:
567/84 + 252/84 = 567 + 252/84 = 819/84
819/84 simplified gives 39/4
So, 81/12 + 21/7 = 39/4
In mixed form: 93/4

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