Subtract 90/27 from 2/21, Solve 2/21

Subtract 90/27 from 2/21

1^st number: 2/21, 2^nd number: 3 9/27

2/21 - 90/27 is -68/21.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 27 is 189

Next, find the equivalent fraction of both fractional numbers with denominator 189
For the 1st fraction, since 21 × 9 = 189,
2/21 = 2 × 9/21 × 9 = 18/189
Likewise, for the 2nd fraction, since 27 × 7 = 189,
90/27 = 90 × 7/27 × 7 = 630/189
Subtract the two like fractions:
18/189 - 630/189 = 18 - 630/189 = -612/189
After reducing the fraction, the answer is -68/21

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