Subtract 21/56 from 18/90
18/90 - 21/56 is -7/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 56 is 2520
Next, find the equivalent fraction of both fractional numbers with denominator 2520 - For the 1st fraction, since 90 × 28 = 2520,
18/90 = 18 × 28/90 × 28 = 504/2520 - Likewise, for the 2nd fraction, since 56 × 45 = 2520,
21/56 = 21 × 45/56 × 45 = 945/2520 - Subtract the two like fractions:
504/2520 - 945/2520 = 504 - 945/2520 = -441/2520 - After reducing the fraction, the answer is -7/40
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