Add 72/21 and 15/54, Solve 3 9/21 + 15/54 as a fraction

Add 72/21 and 15/54

1^st number: 3 9/21, 2^nd number: 15/54

72/21 + 15/54 is 467/126.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 54 is 378

Next, find the equivalent fraction of both fractional numbers with denominator 378
For the 1st fraction, since 21 × 18 = 378,
72/21 = 72 × 18/21 × 18 = 1296/378
Likewise, for the 2nd fraction, since 54 × 7 = 378,
15/54 = 15 × 7/54 × 7 = 105/378
Add the two like fractions:
1296/378 + 105/378 = 1296 + 105/378 = 1401/378
1401/378 simplified gives 467/126
So, 72/21 + 15/54 = 467/126
In mixed form: 389/126

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