Subtract 9/21 from 21/40
21/40 - 9/21 is 27/280.
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,
21/40 = 21 × 21/40 × 21 = 441/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
9/21 = 9 × 40/21 × 40 = 360/840 - Subtract the two like fractions:
441/840 - 360/840 = 441 - 360/840 = 81/840 - After reducing the fraction, the answer is 27/280
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