Subtract 81/80 from 30/72, Solve 30/72

Subtract 81/80 from 30/72

1^st number: 30/72, 2^nd number: 1 1/80

30/72 - 81/80 is -143/240.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 80 is 720

Next, find the equivalent fraction of both fractional numbers with denominator 720
For the 1st fraction, since 72 × 10 = 720,
30/72 = 30 × 10/72 × 10 = 300/720
Likewise, for the 2nd fraction, since 80 × 9 = 720,
81/80 = 81 × 9/80 × 9 = 729/720
Subtract the two like fractions:
300/720 - 729/720 = 300 - 729/720 = -429/720
After reducing the fraction, the answer is -143/240

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