Add 81/21 and 90/5, Solve 3 18/21 + 18 0/5 as a fraction

Add 81/21 and 90/5

1^st number: 3 18/21, 2^nd number: 18 0/5

81/21 + 90/5 is 153/7.

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,
81/21 = 81 × 5/21 × 5 = 405/105
Likewise, for the 2nd fraction, since 5 × 21 = 105,
90/5 = 90 × 21/5 × 21 = 1890/105
Add the two like fractions:
405/105 + 1890/105 = 405 + 1890/105 = 2295/105
2295/105 simplified gives 153/7
So, 81/21 + 90/5 = 153/7
In mixed form: 216/7

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