Add 15/18 and 54/21, Solve 15/18 + 2 12/21 as a fraction

Add 15/18 and 54/21

1^st number: 15/18, 2^nd number: 2 12/21

15/18 + 54/21 is 143/42.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 18 × 7 = 126,
15/18 = 15 × 7/18 × 7 = 105/126
Likewise, for the 2nd fraction, since 21 × 6 = 126,
54/21 = 54 × 6/21 × 6 = 324/126
Add the two like fractions:
105/126 + 324/126 = 105 + 324/126 = 429/126
429/126 simplified gives 143/42
So, 15/18 + 54/21 = 143/42
In mixed form: 317/42

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