Add 10/42 and 40/21, Solve 10/42 + 1 19/21 as a fraction

Add 10/42 and 40/21

1^st number: 10/42, 2^nd number: 1 19/21

10/42 + 40/21 is 15/7.

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,
10/42 = 10 × 1/42 × 1 = 10/42
Likewise, for the 2nd fraction, since 21 × 2 = 42,
40/21 = 40 × 2/21 × 2 = 80/42
Add the two like fractions:
10/42 + 80/42 = 10 + 80/42 = 90/42
90/42 simplified gives 15/7
So, 10/42 + 40/21 = 15/7
In mixed form: 21/7

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