Add 30/9 and 75/21, Solve 3 3/9 + 3 12/21 as a fraction

Add 30/9 and 75/21

1^st number: 3 3/9, 2^nd number: 3 12/21

30/9 + 75/21 is 145/21.

Find the least common denominator or LCM of the two denominators:
LCM of 9 and 21 is 63

Next, find the equivalent fraction of both fractional numbers with denominator 63
For the 1st fraction, since 9 × 7 = 63,
30/9 = 30 × 7/9 × 7 = 210/63
Likewise, for the 2nd fraction, since 21 × 3 = 63,
75/21 = 75 × 3/21 × 3 = 225/63
Add the two like fractions:
210/63 + 225/63 = 210 + 225/63 = 435/63
435/63 simplified gives 145/21
So, 30/9 + 75/21 = 145/21
In mixed form: 619/21

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