Subtract 3/42 from 42/40, Solve 1 2/40

Subtract 3/42 from 42/40

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

42/40 - 3/42 is 137/140.

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,
42/40 = 42 × 21/40 × 21 = 882/840
Likewise, for the 2nd fraction, since 42 × 20 = 840,
3/42 = 3 × 20/42 × 20 = 60/840
Subtract the two like fractions:
882/840 - 60/840 = 882 - 60/840 = 822/840
After reducing the fraction, the answer is 137/140

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