Subtract 18/30 from 21/42
21/42 - 18/30 is -1/10.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
21/42 = 21 × 5/42 × 5 = 105/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
18/30 = 18 × 7/30 × 7 = 126/210 - Subtract the two like fractions:
105/210 - 126/210 = 105 - 126/210 = -21/210 - After reducing the fraction, the answer is -1/10
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