Subtract 9/10 from 42/84
42/84 - 9/10 is -2/5.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 10 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420 - Likewise, for the 2nd fraction, since 10 × 42 = 420,
9/10 = 9 × 42/10 × 42 = 378/420 - Subtract the two like fractions:
210/420 - 378/420 = 210 - 378/420 = -168/420 - After reducing the fraction, the answer is -2/5
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