Subtract 63/42 from 9/40, Solve 9/40

Subtract 63/42 from 9/40

1^st number: 9/40, 2^nd number: 1 21/42

9/40 - 63/42 is -51/40.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 40 × 21 = 840,
9/40 = 9 × 21/40 × 21 = 189/840
Likewise, for the 2nd fraction, since 42 × 20 = 840,
63/42 = 63 × 20/42 × 20 = 1260/840
Subtract the two like fractions:
189/840 - 1260/840 = 189 - 1260/840 = -1071/840
After reducing the fraction, the answer is -51/40

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