Subtract 84/8 from 4/21, Solve 4/21

Subtract 84/8 from 4/21

1^st number: 4/21, 2^nd number: 10 4/8

4/21 - 84/8 is -433/42.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 21 × 8 = 168,
4/21 = 4 × 8/21 × 8 = 32/168
Likewise, for the 2nd fraction, since 8 × 21 = 168,
84/8 = 84 × 21/8 × 21 = 1764/168
Subtract the two like fractions:
32/168 - 1764/168 = 32 - 1764/168 = -1732/168
After reducing the fraction, the answer is -433/42

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