Subtract 20/18 from 21/7
1st number: 3 0/7, 2nd number: 1 2/18
21/7 - 20/18 is 17/9.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 7 × 18 = 126,
21/7 = 21 × 18/7 × 18 = 378/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
20/18 = 20 × 7/18 × 7 = 140/126 - Subtract the two like fractions:
378/126 - 140/126 = 378 - 140/126 = 238/126 - After reducing the fraction, the answer is 17/9
- In mixed form: 18/9
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