Subtract 1/40 from 12/42, Solve 12/42

Subtract 1/40 from 12/42

12/42 - 1/40 is 73/280.

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,
12/42 = 12 × 20/42 × 20 = 240/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840
Subtract the two like fractions:
240/840 - 21/840 = 240 - 21/840 = 219/840
After reducing the fraction, the answer is 73/280

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