Add 21/4 and 18/21, Solve 5 1/4 + 18/21 as a fraction

Add 21/4 and 18/21

1^st number: 5 1/4, 2^nd number: 18/21

21/4 + 18/21 is 171/28.

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,
18/21 = 18 × 4/21 × 4 = 72/84
Add the two like fractions:
441/84 + 72/84 = 441 + 72/84 = 513/84
513/84 simplified gives 171/28
So, 21/4 + 18/21 = 171/28
In mixed form: 63/28

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