Subtract 81/80 from 30/84, Solve 30/84

Subtract 81/80 from 30/84

1^st number: 30/84, 2^nd number: 1 1/80

30/84 - 81/80 is -367/560.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 84 × 20 = 1680,
30/84 = 30 × 20/84 × 20 = 600/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
81/80 = 81 × 21/80 × 21 = 1701/1680
Subtract the two like fractions:
600/1680 - 1701/1680 = 600 - 1701/1680 = -1101/1680
After reducing the fraction, the answer is -367/560

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