Subtract 84/40 from 8/42, Solve 8/42

Subtract 84/40 from 8/42

1^st number: 8/42, 2^nd number: 2 4/40

8/42 - 84/40 is -401/210.

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

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 42 × 20 = 840,
8/42 = 8 × 20/42 × 20 = 160/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
84/40 = 84 × 21/40 × 21 = 1764/840
Subtract the two like fractions:
160/840 - 1764/840 = 160 - 1764/840 = -1604/840
After reducing the fraction, the answer is -401/210

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