Algebra
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Unit 1: Foundations for Algebra
Lesson 1.5: Adding & Subtracting Real Numbers
Addition and Subtraction are the very fundamentals on which algebra is built.
Either it's going up or it's going down. Positives up and negatives down. When we are adding or subtracting terms, it is important to remember there are only two directions on a number line. It helps to think of money: positives are bonuses and negatives are debts. |
We can go up and up:
+5 + 3 = +8
We can go up and down.
If you make more money than you spent, you will have a positive balance.
If you spend more money than you made, you will have a negative balance.
+5 - 3 = 2.
And we can go down and down:
-5 - 3 = -8