Subtract 18/40 from 10/21
10/21 - 18/40 is 11/420.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
10/21 = 10 × 40/21 × 40 = 400/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
18/40 = 18 × 21/40 × 21 = 378/840 - Subtract the two like fractions:
400/840 - 378/840 = 400 - 378/840 = 22/840 - After reducing the fraction, the answer is 11/420
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