Subtract 90/80 from 18/49, Solve 18/49

Subtract 90/80 from 18/49

1^st number: 18/49, 2^nd number: 1 10/80

18/49 - 90/80 is -297/392.

Find the least common denominator or LCM of the two denominators:
LCM of 49 and 80 is 3920

Next, find the equivalent fraction of both fractional numbers with denominator 3920
For the 1st fraction, since 49 × 80 = 3920,
18/49 = 18 × 80/49 × 80 = 1440/3920
Likewise, for the 2nd fraction, since 80 × 49 = 3920,
90/80 = 90 × 49/80 × 49 = 4410/3920
Subtract the two like fractions:
1440/3920 - 4410/3920 = 1440 - 4410/3920 = -2970/3920
After reducing the fraction, the answer is -297/392

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