Add 15/21 and 42/27, Solve 15/21 + 1 15/27 as a fraction

Add 15/21 and 42/27

1^st number: 15/21, 2^nd number: 1 15/27

15/21 + 42/27 is 143/63.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 27 is 189

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 21 × 9 = 189,
15/21 = 15 × 9/21 × 9 = 135/189
Likewise, for the 2nd fraction, since 27 × 7 = 189,
42/27 = 42 × 7/27 × 7 = 294/189
Add the two like fractions:
135/189 + 294/189 = 135 + 294/189 = 429/189
429/189 simplified gives 143/63
So, 15/21 + 42/27 = 143/63
In mixed form: 217/63

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