Subtract 15/20 from 42/21
1st number: 2 0/21, 2nd number: 15/20
42/21 - 15/20 is 5/4.
Steps for subtracting fractions
- 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,
42/21 = 42 × 20/21 × 20 = 840/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
15/20 = 15 × 21/20 × 21 = 315/420 - Subtract the two like fractions:
840/420 - 315/420 = 840 - 315/420 = 525/420 - After reducing the fraction, the answer is 5/4
- In mixed form: 11/4
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