Subtract 15/21 from 18/90
18/90 - 15/21 is -18/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
18/90 = 18 × 7/90 × 7 = 126/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
15/21 = 15 × 30/21 × 30 = 450/630 - Subtract the two like fractions:
126/630 - 450/630 = 126 - 450/630 = -324/630 - After reducing the fraction, the answer is -18/35
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