Subtract 21/45 from 18/42
18/42 - 21/45 is -4/105.
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,
18/42 = 18 × 15/42 × 15 = 270/630 - Likewise, for the 2nd fraction, since 45 × 14 = 630,
21/45 = 21 × 14/45 × 14 = 294/630 - Subtract the two like fractions:
270/630 - 294/630 = 270 - 294/630 = -24/630 - After reducing the fraction, the answer is -4/105
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