Subtract 20/8 from 1/81, Solve 1/81

Subtract 20/8 from 1/81

1^st number: 1/81, 2^nd number: 2 4/8

1/81 - 20/8 is -403/162.

Find the least common denominator or LCM of the two denominators:
LCM of 81 and 8 is 648

Next, find the equivalent fraction of both fractional numbers with denominator 648
For the 1st fraction, since 81 × 8 = 648,
1/81 = 1 × 8/81 × 8 = 8/648
Likewise, for the 2nd fraction, since 8 × 81 = 648,
20/8 = 20 × 81/8 × 81 = 1620/648
Subtract the two like fractions:
8/648 - 1620/648 = 8 - 1620/648 = -1612/648
After reducing the fraction, the answer is -403/162

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