Subtract 70/21 from 10/80, Solve 10/80

Subtract 70/21 from 10/80

1^st number: 10/80, 2^nd number: 3 7/21

10/80 - 70/21 is -77/24.

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,
10/80 = 10 × 21/80 × 21 = 210/1680
Likewise, for the 2nd fraction, since 21 × 80 = 1680,
70/21 = 70 × 80/21 × 80 = 5600/1680
Subtract the two like fractions:
210/1680 - 5600/1680 = 210 - 5600/1680 = -5390/1680
After reducing the fraction, the answer is -77/24

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