Add 21/42 and 80/81, Solve 21/42 + 80/81 as a fraction

Add 21/42 and 80/81

21/42 + 80/81 is 241/162.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 81 is 1134

Next, find the equivalent fraction of both fractional numbers with denominator 1134
For the 1st fraction, since 42 × 27 = 1134,
21/42 = 21 × 27/42 × 27 = 567/1134
Likewise, for the 2nd fraction, since 81 × 14 = 1134,
80/81 = 80 × 14/81 × 14 = 1120/1134
Add the two like fractions:
567/1134 + 1120/1134 = 567 + 1120/1134 = 1687/1134
1687/1134 simplified gives 241/162
So, 21/42 + 80/81 = 241/162
In mixed form: 179/162

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