Add 30/90 and 72/21, Solve 30/90 + 3 9/21 as a fraction

Add 30/90 and 72/21

1^st number: 30/90, 2^nd number: 3 9/21

30/90 + 72/21 is 79/21.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 90 × 7 = 630,
30/90 = 30 × 7/90 × 7 = 210/630
Likewise, for the 2nd fraction, since 21 × 30 = 630,
72/21 = 72 × 30/21 × 30 = 2160/630
Add the two like fractions:
210/630 + 2160/630 = 210 + 2160/630 = 2370/630
2370/630 simplified gives 79/21
So, 30/90 + 72/21 = 79/21
In mixed form: 316/21

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