Add 6/20 and 72/21, Solve 6/20 + 3 9/21 as a fraction

Add 6/20 and 72/21

1^st number: 6/20, 2^nd number: 3 9/21

6/20 + 72/21 is 261/70.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 20 × 21 = 420,
6/20 = 6 × 21/20 × 21 = 126/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
72/21 = 72 × 20/21 × 20 = 1440/420
Add the two like fractions:
126/420 + 1440/420 = 126 + 1440/420 = 1566/420
1566/420 simplified gives 261/70
So, 6/20 + 72/21 = 261/70
In mixed form: 351/70

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