1. Adding & Subtracting –ve no.s
= 7
= -3
= -10 + + −
Here explain how to use it, the first number in an addition/sub sum is the starting number, point your finger on the starting number, the sign of the second number tells you in which direction you are going to go ! - +
= ? = ? = ?

2. Summary −3 – 4 = − 7 +3+4 = +7 −3+4 = +1 3−4 = −1
(keep walking in the negative direction)
+3+4 = +7
(keep walking in the positive direction)
−3+4 = +1
(If the bigger number has a positive sign, just minus the numbers, the answer is positive)
3−4 = −1
(if the bigger number has a negative sign, minus the numbers number, the answer is negative)

3. I will still have €3 debt ! (-3)
Reason it out..
𝒂.) 𝟖 – 𝟏𝟏 = −𝟑
A.) Using the Number Line
B.) Using Money
I have €8 in my pocket (+8)
I have €11 debt (-11) (money to give : dejn!)
I can give the €8 I have in my pocket BUT
I will still have €3 debt ! (-3)

4. Reason it out..
𝒃.)−𝟑 + 𝟓=𝟐 A.) Using the Number Line B.) Using Money I have €3 debt (-3) (money to give : dejn!) I have €5 in my pocket (+5) I can give the €3 from my pocket AND I will still have €2 left in my pocket! (2)

5. Reason it out..
𝒄.) −𝟓−𝟐+𝟑+𝟏=−𝟑 A.) Using the Number Line B.) Using Money I have €𝟓 𝐝𝐞𝐛𝐭 I have €𝟐 𝒅𝒆𝒃𝒕 In all I have €7 debt
I have €𝟑 𝐢𝐧 𝐦𝐲 𝐩𝐨𝐜𝐤𝐞𝐭
I have €𝟏 𝒊𝒏 𝒎𝒚 𝒑𝒐𝒄𝒌𝒆𝒕
In all I have €𝟒
I can pay €4 BUT will still need to pay €3 (-3)

6. What about when the signs are together?
Two positives?
Two negatives?
Neg & pos?
Pos & Neg?

7. I do not (-) not (-) want a chocolate I WANT (+ve) a chocolate !!!!
Two negatives?
I do not (-) not (-) want a chocolate
means
I WANT (+ve) a chocolate !!!!

8. Friend or Enemy?

9. + = 14
Look at the signs in the middle, if they are the same, then replace them with +

10. - = 2
Look at the signs in the middle, if they are different, then replace them with -

11. -6 + -2 = -6 - -8 = -8 2 But what about this one? - += -8 2 +
Remember: This is your start number and
the new sign in the middle is the direction

12. Summary – When signs are together
They become ONE SIGN SAME SIGNS  BECOME A PLUS DIFFERENT SIGNS  BECOME A MINUS

13. MINI-PLENARY (SIMPSONS)
Work out:
-5 – 9
a) 14
b) 45
c) -45
d) -14

14. MINI-PLENARY (SIMPSONS)
Work out:
a) 17
b) -1
d) 1
c) -17

15. Multiplication is repeated addition
What is 2 x 4?
Read this question using normal words:
“2 for 4 times” 2
+ 2
+ 2
+ 2
= 8
Multiplication is repeated addition

16. What is -2 x 4?
Read this question using normal words:
“ minus 2 for 4 times ” -2 -2 -2 -2
= -8

17. Multiplying and Dividing
SAME SIGNS
DIFFERENT SIGNS
POSITIVE ANSWER
8 x 2 = (+ × + = +)
-8 x -2 = 16 − × − = +
24 ÷ 6 = 4 + ÷ + = +
-24 ÷ -6 = 4 (− ÷ − = +)
NEGATIVE ANSWER
-8 x 2 = -16 − × + = −
2 x -8 = -16 ( + × − = −)
-24 ÷ 6 = - 4 (− ÷ + = −)
24 ÷ -6 = - 4 ( + ÷ − = −)