Add 70/21 and 18/5, Solve 3 7/21 + 3 3/5 as a fraction

Add 70/21 and 18/5

1^st number: 3 7/21, 2^nd number: 3 3/5

70/21 + 18/5 is 104/15.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 21 × 5 = 105,
70/21 = 70 × 5/21 × 5 = 350/105
Likewise, for the 2nd fraction, since 5 × 21 = 105,
18/5 = 18 × 21/5 × 21 = 378/105
Add the two like fractions:
350/105 + 378/105 = 350 + 378/105 = 728/105
728/105 simplified gives 104/15
So, 70/21 + 18/5 = 104/15
In mixed form: 614/15

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