Subtract 45/42 from 4/80, Solve 4/80

Subtract 45/42 from 4/80

1^st number: 4/80, 2^nd number: 1 3/42

4/80 - 45/42 is -143/140.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 42 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 80 × 21 = 1680,
4/80 = 4 × 21/80 × 21 = 84/1680
Likewise, for the 2nd fraction, since 42 × 40 = 1680,
45/42 = 45 × 40/42 × 40 = 1800/1680
Subtract the two like fractions:
84/1680 - 1800/1680 = 84 - 1800/1680 = -1716/1680
After reducing the fraction, the answer is -143/140

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