Subtract 81/21 from 15/90
1st number: 15/90, 2nd number: 3 18/21
15/90 - 81/21 is -155/42.
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,
15/90 = 15 × 7/90 × 7 = 105/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
81/21 = 81 × 30/21 × 30 = 2430/630 - Subtract the two like fractions:
105/630 - 2430/630 = 105 - 2430/630 = -2325/630 - After reducing the fraction, the answer is -155/42
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