Add 18/21 and 81/20, Solve 18/21 + 4 1/20 as a fraction

Add 18/21 and 81/20

1^st number: 18/21, 2^nd number: 4 1/20

18/21 + 81/20 is 687/140.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
18/21 = 18 × 20/21 × 20 = 360/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
81/20 = 81 × 21/20 × 21 = 1701/420
Add the two like fractions:
360/420 + 1701/420 = 360 + 1701/420 = 2061/420
2061/420 simplified gives 687/140
So, 18/21 + 81/20 = 687/140
In mixed form: 4127/140

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