Add 20/42 and 28/21, Solve 20/42 + 1 7/21 as a fraction

Add 20/42 and 28/21

1^st number: 20/42, 2^nd number: 1 7/21

20/42 + 28/21 is 38/21.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42

Next, find the equivalent fraction of both fractional numbers with denominator 42
For the 1st fraction, since 42 × 1 = 42,
20/42 = 20 × 1/42 × 1 = 20/42
Likewise, for the 2nd fraction, since 21 × 2 = 42,
28/21 = 28 × 2/21 × 2 = 56/42
Add the two like fractions:
20/42 + 56/42 = 20 + 56/42 = 76/42
76/42 simplified gives 38/21
So, 20/42 + 28/21 = 38/21
In mixed form: 117/21

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