Subtract 20/21 from 70/80
70/80 - 20/21 is -13/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 21 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 80 × 21 = 1680,
70/80 = 70 × 21/80 × 21 = 1470/1680 - Likewise, for the 2nd fraction, since 21 × 80 = 1680,
20/21 = 20 × 80/21 × 80 = 1600/1680 - Subtract the two like fractions:
1470/1680 - 1600/1680 = 1470 - 1600/1680 = -130/1680 - After reducing the fraction, the answer is -13/168
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