Subtract 30/36 from 21/49, Solve 21/49

Subtract 30/36 from 21/49

21/49 - 30/36 is -17/42.

Find the least common denominator or LCM of the two denominators:
LCM of 49 and 36 is 1764

Next, find the equivalent fraction of both fractional numbers with denominator 1764
For the 1st fraction, since 49 × 36 = 1764,
21/49 = 21 × 36/49 × 36 = 756/1764
Likewise, for the 2nd fraction, since 36 × 49 = 1764,
30/36 = 30 × 49/36 × 49 = 1470/1764
Subtract the two like fractions:
756/1764 - 1470/1764 = 756 - 1470/1764 = -714/1764
After reducing the fraction, the answer is -17/42

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