Subtract 42/80 from 8/21
8/21 - 42/80 is -121/840.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 21 × 80 = 1680,
8/21 = 8 × 80/21 × 80 = 640/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
42/80 = 42 × 21/80 × 21 = 882/1680 - Subtract the two like fractions:
640/1680 - 882/1680 = 640 - 882/1680 = -242/1680 - After reducing the fraction, the answer is -121/840
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