Subtract 25/20 from 18/21
1st number: 18/21, 2nd number: 1 5/20
18/21 - 25/20 is -11/28.
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,
18/21 = 18 × 20/21 × 20 = 360/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
25/20 = 25 × 21/20 × 21 = 525/420 - Subtract the two like fractions:
360/420 - 525/420 = 360 - 525/420 = -165/420 - After reducing the fraction, the answer is -11/28
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