Add 21/4 and 28/21, Solve 5 1/4 + 1 7/21 as a fraction

Add 21/4 and 28/21

1^st number: 5 1/4, 2^nd number: 1 7/21

21/4 + 28/21 is 79/12.

Find the least common denominator or LCM of the two denominators:
LCM of 4 and 21 is 84

Next, find the equivalent fraction of both fractional numbers with denominator 84
For the 1st fraction, since 4 × 21 = 84,
21/4 = 21 × 21/4 × 21 = 441/84
Likewise, for the 2nd fraction, since 21 × 4 = 84,
28/21 = 28 × 4/21 × 4 = 112/84
Add the two like fractions:
441/84 + 112/84 = 441 + 112/84 = 553/84
553/84 simplified gives 79/12
So, 21/4 + 28/21 = 79/12
In mixed form: 67/12

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