Add 81/21 and 42/14, Solve 3 18/21 + 3 0/14 as a fraction

Add 81/21 and 42/14

1^st number: 3 18/21, 2^nd number: 3 0/14

81/21 + 42/14 is 48/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 14 is 42

Next, find the equivalent fraction of both fractional numbers with denominator 42
For the 1st fraction, since 21 × 2 = 42,
81/21 = 81 × 2/21 × 2 = 162/42
Likewise, for the 2nd fraction, since 14 × 3 = 42,
42/14 = 42 × 3/14 × 3 = 126/42
Add the two like fractions:
162/42 + 126/42 = 162 + 126/42 = 288/42
288/42 simplified gives 48/7
So, 81/21 + 42/14 = 48/7
In mixed form: 66/7

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