Subtract 84/9 from 40/42, Solve 40/42

Subtract 84/9 from 40/42

1^st number: 40/42, 2^nd number: 9 3/9

40/42 - 84/9 is -176/21.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 9 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 42 × 3 = 126,
40/42 = 40 × 3/42 × 3 = 120/126
Likewise, for the 2nd fraction, since 9 × 14 = 126,
84/9 = 84 × 14/9 × 14 = 1176/126
Subtract the two like fractions:
120/126 - 1176/126 = 120 - 1176/126 = -1056/126
After reducing the fraction, the answer is -176/21

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