Subtract 21/10 from 1/42, Solve 1/42

Subtract 21/10 from 1/42

1^st number: 1/42, 2^nd number: 2 1/10

1/42 - 21/10 is -218/105.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 10 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 42 × 5 = 210,
1/42 = 1 × 5/42 × 5 = 5/210
Likewise, for the 2nd fraction, since 10 × 21 = 210,
21/10 = 21 × 21/10 × 21 = 441/210
Subtract the two like fractions:
5/210 - 441/210 = 5 - 441/210 = -436/210
After reducing the fraction, the answer is -218/105

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