1. Starter 7x – 9x -2x + 10x 3y - - 5y -6p + 2p -10t + t
Adding and Subtracting negative numbers:
EXTRA:
7x – 9x
-2x + 10x
3y - - 5y
-6p + 2p
-10t + t
-2k + s – 7k – 8s
6 – 22
1 = 21
2 = 21
3 = -35
4 = 19
5 = 36
6 = -19
7 = -16
8 = 0
9 = 0
10 = 19.5
-2x 8x 8y
-4p
-9t
-9k – 7s

2. If the signs are the SAME the answer is POSITIVE
LO: to be able to multiply and divide negative numbers.
The Rules:
Multiplying
+ve x +ve = +ve
-ve x -ve = +ve
+ve x -ve = -ve
-ve x +ve = -ve
Dividing
+ve ÷ +ve = +ve
-ve ÷ -ve = +ve
+ve ÷ -ve = -ve
-ve ÷ +ve = -ve
If the signs are the SAME the answer is POSITIVE
If the signs are DIFFERENT the answer is NEGATIVE

3. = 48 -12 x -4 -ve x -ve = +ve Example 1
The signs are the same so the answer is POSITIVE!
Just do as you would normally do when multiplying the numbers.
= 48
Try:
1) -7 x ) -9 x ) -11 x ) -2 x -5y

4. 63 ÷ -7 = -9 +ve ÷ -ve = -ve Example 2
Do the calculation as if it was just 63 ÷ 7. (= 9)
Decide which rule you need to use.
+ve ÷ -ve = -ve
(The signs are different so the answer is NEGATIVE)
= -9

5. Questions Answers 3 x – 4 -12 -7 x -2 14 9 x 9 81 6 x -6 -36
-20 ÷ 5
-100 ÷ -10
-10 x 2
-11 x -19
- 450 ÷ - 5
36 ÷ -6
-7 x 11
-12 x 11
-3 x -20
-6 x -3 ÷ 2
Answers
-12 14 81
-36 -4 10
-20
209 90 -6
-77
-132 60 9

6. Can you do these??
1892 ÷ (-3)
(-9)²

7. Negative numbers and Algebra:
Sometimes you need to remember these rules in order to simplify algebra.
Example:
-2 ( 5x – 4)
9 ( 2y – 7)
(x – 4) ( x – 2)