Subtract 30/80 from 7/21
7/21 - 30/80 is -1/24.
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,
7/21 = 7 × 80/21 × 80 = 560/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
30/80 = 30 × 21/80 × 21 = 630/1680 - Subtract the two like fractions:
560/1680 - 630/1680 = 560 - 630/1680 = -70/1680 - After reducing the fraction, the answer is -1/24
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