Subtract 21/7 from 18/21
1st number: 18/21, 2nd number: 3 0/7
18/21 - 21/7 is -15/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
18/21 = 18 × 1/21 × 1 = 18/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
21/7 = 21 × 3/7 × 3 = 63/21 - Subtract the two like fractions:
18/21 - 63/21 = 18 - 63/21 = -45/21 - After reducing the fraction, the answer is -15/7
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