Subtract 42/90 from 21/49
21/49 - 42/90 is -4/105.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 49 and 90 is 4410
Next, find the equivalent fraction of both fractional numbers with denominator 4410 - For the 1st fraction, since 49 × 90 = 4410,
21/49 = 21 × 90/49 × 90 = 1890/4410 - Likewise, for the 2nd fraction, since 90 × 49 = 4410,
42/90 = 42 × 49/90 × 49 = 2058/4410 - Subtract the two like fractions:
1890/4410 - 2058/4410 = 1890 - 2058/4410 = -168/4410 - After reducing the fraction, the answer is -4/105
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