Add 21/12 and 80/70, Solve 1 9/12 + 1 10/70 as a fraction

Add 21/12 and 80/70

1^st number: 1 9/12, 2^nd number: 1 10/70

21/12 + 80/70 is 81/28.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 70 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 12 × 35 = 420,
21/12 = 21 × 35/12 × 35 = 735/420
Likewise, for the 2nd fraction, since 70 × 6 = 420,
80/70 = 80 × 6/70 × 6 = 480/420
Add the two like fractions:
735/420 + 480/420 = 735 + 480/420 = 1215/420
1215/420 simplified gives 81/28
So, 21/12 + 80/70 = 81/28
In mixed form: 225/28

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