1. 7.1.3 Subtracting Integers

2. Basic Rules

3. Negative Minus a Positive (Number Line)
–3 – 1 = ?

4. Subtracting a Number & Adding its Opposite
Subtracting 3 is the same as adding -3
Subtracting 9 is the same as adding -9
Subtracting 4 is the same as adding -4

5. Why It Works (With Counters)+ + + + + + + + – + – – – – + –
4 + –2 = 2
= 2
= 0
You can actually have as many negatives as you want as long as there is a positive attached to it. The group will always equal 0

6. Positive Minus Negative (Counters)
Now, when you take the negatives away, what are you left with?
7 positives
3 – (– 4) = ? + + + + + + + + + + – – – – + + + +
You need to have the -4 present, but because they aren’t a part of the original 3, they need to have positives attached to them to keep the total of the group at 0
3 – (– 4) = 7
Is the same as
3 + 4 = 7

7. Simply Put…
When subtracting a negative, change the subtraction and negative sign into an addition sign. Think of it as combining both lines into one symbol

8. Negative Minus a Negative
Same as a positive minus a negative. Combine the minus sign and the negative sign into an addition sign. So… Negative – Negative = Negative + Positive

9. Your Turn!

10. Homework
Page 18 (#4, 5, 6, 7, 19, 22 24, 25, 32, 39)