Subtract 21/90 from 7/42
7/42 - 21/90 is -1/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
7/42 = 7 × 15/42 × 15 = 105/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
21/90 = 21 × 7/90 × 7 = 147/630 - Subtract the two like fractions:
105/630 - 147/630 = 105 - 147/630 = -42/630 - After reducing the fraction, the answer is -1/15
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