Subtract 90/40 from 18/63, Solve 18/63

Subtract 90/40 from 18/63

1^st number: 18/63, 2^nd number: 2 10/40

18/63 - 90/40 is -55/28.

Find the least common denominator or LCM of the two denominators:
LCM of 63 and 40 is 2520

Next, find the equivalent fraction of both fractional numbers with denominator 2520
For the 1st fraction, since 63 × 40 = 2520,
18/63 = 18 × 40/63 × 40 = 720/2520
Likewise, for the 2nd fraction, since 40 × 63 = 2520,
90/40 = 90 × 63/40 × 63 = 5670/2520
Subtract the two like fractions:
720/2520 - 5670/2520 = 720 - 5670/2520 = -4950/2520
After reducing the fraction, the answer is -55/28

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