Add 18/15 and 21/40, Solve 1 3/15 + 21/40 as a fraction

Add 18/15 and 21/40

1^st number: 1 3/15, 2^nd number: 21/40

18/15 + 21/40 is 69/40.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 40 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 15 × 8 = 120,
18/15 = 18 × 8/15 × 8 = 144/120
Likewise, for the 2nd fraction, since 40 × 3 = 120,
21/40 = 21 × 3/40 × 3 = 63/120
Add the two like fractions:
144/120 + 63/120 = 144 + 63/120 = 207/120
207/120 simplified gives 69/40
So, 18/15 + 21/40 = 69/40
In mixed form: 129/40

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