Subtract 81/49 from 18/40, Solve 18/40

Subtract 81/49 from 18/40

1^st number: 18/40, 2^nd number: 1 32/49

18/40 - 81/49 is -1179/980.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 49 is 1960

Next, find the equivalent fraction of both fractional numbers with denominator 1960
For the 1st fraction, since 40 × 49 = 1960,
18/40 = 18 × 49/40 × 49 = 882/1960
Likewise, for the 2nd fraction, since 49 × 40 = 1960,
81/49 = 81 × 40/49 × 40 = 3240/1960
Subtract the two like fractions:
882/1960 - 3240/1960 = 882 - 3240/1960 = -2358/1960
After reducing the fraction, the answer is -1179/980

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