Subtract 21/45 from 15/42
15/42 - 21/45 is -23/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 45 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
15/42 = 15 × 15/42 × 15 = 225/630 - Likewise, for the 2nd fraction, since 45 × 14 = 630,
21/45 = 21 × 14/45 × 14 = 294/630 - Subtract the two like fractions:
225/630 - 294/630 = 225 - 294/630 = -69/630 - After reducing the fraction, the answer is -23/210
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