Add 12/21 and 21/15, Solve 12/21 + 1 6/15 as a fraction

Add 12/21 and 21/15

1^st number: 12/21, 2^nd number: 1 6/15

12/21 + 21/15 is 69/35.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 21 × 5 = 105,
12/21 = 12 × 5/21 × 5 = 60/105
Likewise, for the 2nd fraction, since 15 × 7 = 105,
21/15 = 21 × 7/15 × 7 = 147/105
Add the two like fractions:
60/105 + 147/105 = 60 + 147/105 = 207/105
207/105 simplified gives 69/35
So, 12/21 + 21/15 = 69/35
In mixed form: 134/35

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