Subtracting mixed numbers involves a few key steps to ensure accuracy. The basic principle is to subtract the whole numbers and the fractions separately, but sometimes you need to adjust the numbers first.
Here's a breakdown of how to subtract mixed numbers, suitable for a 7th-grade understanding:
Steps to Subtract Mixed Numbers
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Check the Fractions: Ensure that the fraction you are subtracting is not larger than the fraction you are subtracting from. If this is the case, you will need to borrow from the whole number.
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Borrowing (If Necessary): If the fraction you are subtracting is larger than the fraction you are subtracting from, you'll need to borrow 1 from the whole number. To do this:
- Reduce the whole number by 1.
- Convert the borrowed 1 into a fraction with the same denominator as the existing fraction.
- Add this new fraction to the existing fraction.
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Subtract the Fractions: Once the fractions are in order (the top fraction is larger or equal to the bottom fraction), subtract the numerators (the top numbers) of the fractions. Keep the denominator (the bottom number) the same.
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Subtract the Whole Numbers: Subtract the whole numbers.
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Simplify (If Possible): Simplify the fraction if it is improper (numerator larger than the denominator) or can be reduced to lower terms.
Example
Let's say you want to solve: 9 1/7 - 3/7.
According to the Math Antics video (6:30-9:12), if you have 8/7 - 3/7, you simply subtract the numerators:
- 8/7 - 3/7 = 5/7.
Then, you subtract the whole numbers.
- 9 - 0 = 9
Answer: 9 1/7 - 3/7 = 9 5/7.
