Subtract 70/21 from 20/8, Solve 2 4/8

Subtract 70/21 from 20/8

1^st number: 2 4/8, 2^nd number: 3 7/21

20/8 - 70/21 is -5/6.

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

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 8 × 21 = 168,
20/8 = 20 × 21/8 × 21 = 420/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
70/21 = 70 × 8/21 × 8 = 560/168
Subtract the two like fractions:
420/168 - 560/168 = 420 - 560/168 = -140/168
After reducing the fraction, the answer is -5/6

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