Subtract 21/7 from 42/90
1st number: 42/90, 2nd number: 3 0/7
42/90 - 21/7 is -38/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 7 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
42/90 = 42 × 7/90 × 7 = 294/630 - Likewise, for the 2nd fraction, since 7 × 90 = 630,
21/7 = 21 × 90/7 × 90 = 1890/630 - Subtract the two like fractions:
294/630 - 1890/630 = 294 - 1890/630 = -1596/630 - After reducing the fraction, the answer is -38/15
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