Cumulative Practice
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- 12
- 5+( - 7)= - 5- 7 Finally, we can calculate the difference. - 5- 7=- 12 We can see that adding a negative number is the same as subtracting its positive counterpart. Below we can demonstrate this by finding - 5 and moving 7 units to the left on the number line. Let's draw an arrow from 0 to - 4 on the the number line!
Next we can draw an arrow 7 units to the left to represent adding - 7.
When we are performing mathematical operations using real numbers, we always need to make sure that we are following the Properties of Real Numbers.
These properties tell us the legal
moves we can make when adding or multiplying numbers.
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But why aren't there properties for subtraction or division? |
Some mathematicians refuse to acknowledge that subtraction and division are even operations! Subtraction is the same thing as adding a negative and division is the same thing as multiplying by a fraction. a-b=a+(- b) and a/b=a* 1/b Therefore, we can use the Properties of Real Numbers for subtraction and division, but we need to change our way of thinking.