Subtract 80/7 from 90/18, Solve 5 0/18

Subtract 80/7 from 90/18

1^st number: 5 0/18, 2^nd number: 11 3/7

90/18 - 80/7 is -45/7.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 7 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 18 × 7 = 126,
90/18 = 90 × 7/18 × 7 = 630/126
Likewise, for the 2nd fraction, since 7 × 18 = 126,
80/7 = 80 × 18/7 × 18 = 1440/126
Subtract the two like fractions:
630/126 - 1440/126 = 630 - 1440/126 = -810/126
After reducing the fraction, the answer is -45/7

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