Subtract 8/21 from 18/40
18/40 - 8/21 is 29/420.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
18/40 = 18 × 21/40 × 21 = 378/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
8/21 = 8 × 40/21 × 40 = 320/840 - Subtract the two like fractions:
378/840 - 320/840 = 378 - 320/840 = 58/840 - After reducing the fraction, the answer is 29/420
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