Subtract 18/20 from 10/21
10/21 - 18/20 is -89/210.
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,
10/21 = 10 × 20/21 × 20 = 200/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
18/20 = 18 × 21/20 × 21 = 378/420 - Subtract the two like fractions:
200/420 - 378/420 = 200 - 378/420 = -178/420 - After reducing the fraction, the answer is -89/210
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