Add 21/12 and 30/8, Solve 1 9/12 + 3 6/8 as a fraction

Add 21/12 and 30/8

1^st number: 1 9/12, 2^nd number: 3 6/8

21/12 + 30/8 is 11/2.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 8 is 24

Next, find the equivalent fraction of both fractional numbers with denominator 24
For the 1st fraction, since 12 × 2 = 24,
21/12 = 21 × 2/12 × 2 = 42/24
Likewise, for the 2nd fraction, since 8 × 3 = 24,
30/8 = 30 × 3/8 × 3 = 90/24
Add the two like fractions:
42/24 + 90/24 = 42 + 90/24 = 132/24
132/24 simplified gives 11/2
So, 21/12 + 30/8 = 11/2
In mixed form: 51/2

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