Add 15/20 and 21/42
15/20 + 21/42 is 5/4.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 42 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Likewise, for the 2nd fraction, since 42 × 10 = 420,
21/42 = 21 × 10/42 × 10 = 210/420 - Add the two like fractions:
315/420 + 210/420 = 315 + 210/420 = 525/420 - 525/420 simplified gives 5/4
- So, 15/20 + 21/42 = 5/4
In mixed form: 11/4
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