Subtract 21/27 from 1/7, Solve 1/7

Subtract 21/27 from 1/7

1/7 - 21/27 is -40/63.

Find the least common denominator or LCM of the two denominators:
LCM of 7 and 27 is 189

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 7 × 27 = 189,
1/7 = 1 × 27/7 × 27 = 27/189
Likewise, for the 2nd fraction, since 27 × 7 = 189,
21/27 = 21 × 7/27 × 7 = 147/189
Subtract the two like fractions:
27/189 - 147/189 = 27 - 147/189 = -120/189
After reducing the fraction, the answer is -40/63

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