Subtract 21/10 from 18/42
1st number: 18/42, 2nd number: 2 1/10
18/42 - 21/10 is -117/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 10 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
18/42 = 18 × 5/42 × 5 = 90/210 - Likewise, for the 2nd fraction, since 10 × 21 = 210,
21/10 = 21 × 21/10 × 21 = 441/210 - Subtract the two like fractions:
90/210 - 441/210 = 90 - 441/210 = -351/210 - After reducing the fraction, the answer is -117/70
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