Subtract 42/21 from 8/10, Solve 8/10

Subtract 42/21 from 8/10

1^st number: 8/10, 2^nd number: 2 0/21

8/10 - 42/21 is -6/5.

Find the least common denominator or LCM of the two denominators:
LCM of 10 and 21 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 10 × 21 = 210,
8/10 = 8 × 21/10 × 21 = 168/210
Likewise, for the 2nd fraction, since 21 × 10 = 210,
42/21 = 42 × 10/21 × 10 = 420/210
Subtract the two like fractions:
168/210 - 420/210 = 168 - 420/210 = -252/210
After reducing the fraction, the answer is -6/5

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