Subtract 27/20 from 30/42, Solve 30/42

Subtract 27/20 from 30/42

1^st number: 30/42, 2^nd number: 1 7/20

30/42 - 27/20 is -89/140.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 42 × 10 = 420,
30/42 = 30 × 10/42 × 10 = 300/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
27/20 = 27 × 21/20 × 21 = 567/420
Subtract the two like fractions:
300/420 - 567/420 = 300 - 567/420 = -267/420
After reducing the fraction, the answer is -89/140

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