Subtract 21/27 from 15/30, Solve 15/30

Subtract 21/27 from 15/30

15/30 - 21/27 is -5/18.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 27 is 270

Next, find the equivalent fraction of both fractional numbers with denominator 270
For the 1st fraction, since 30 × 9 = 270,
15/30 = 15 × 9/30 × 9 = 135/270
Likewise, for the 2nd fraction, since 27 × 10 = 270,
21/27 = 21 × 10/27 × 10 = 210/270
Subtract the two like fractions:
135/270 - 210/270 = 135 - 210/270 = -75/270
After reducing the fraction, the answer is -5/18

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