Add 70/21 and 9/80, Solve 3 7/21 + 9/80 as a fraction

Add 70/21 and 9/80

1^st number: 3 7/21, 2^nd number: 9/80

70/21 + 9/80 is 827/240.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 21 × 80 = 1680,
70/21 = 70 × 80/21 × 80 = 5600/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
9/80 = 9 × 21/80 × 21 = 189/1680
Add the two like fractions:
5600/1680 + 189/1680 = 5600 + 189/1680 = 5789/1680
5789/1680 simplified gives 827/240
So, 70/21 + 9/80 = 827/240
In mixed form: 3107/240

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