Subtract 30/50 from 42/84, Solve 42/84

Subtract 30/50 from 42/84

42/84 - 30/50 is -1/10.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 50 is 2100

Next, find the equivalent fraction of both fractional numbers with denominator 2100
For the 1st fraction, since 84 × 25 = 2100,
42/84 = 42 × 25/84 × 25 = 1050/2100
Likewise, for the 2nd fraction, since 50 × 42 = 2100,
30/50 = 30 × 42/50 × 42 = 1260/2100
Subtract the two like fractions:
1050/2100 - 1260/2100 = 1050 - 1260/2100 = -210/2100
After reducing the fraction, the answer is -1/10

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