Numbers to the left of zero on a number line are negative, while numbers to the right are positive. Negative numbers multiplied together are positive, while a negative number multiplied by a positive number or vice versa results in a negative product. Division follows similar rules, with a negative number divided by a positive resulting in a negative quotient. When combining operations, calculations in brackets are performed first, followed by multiplication/division from left to right, and finally addition/subtraction from left to right.

1. Directed Numbers

2. Number with negative sign, ‘ – ’ , is a negative number .
Number on the left side of a number line is less than the one on the right. Numbers on the bottom of
a number line is less than the one on top.
Positive numbers
Negative
numbers Positive numbers
0
Negative numbers

3. Rules for multiplication: a and b are positive numbers
a) 𝑎 ×𝑏 = 𝑎𝑏
b) −𝑎 ×𝑏 = −𝑎𝑏
c) −𝑎 𝑥 −𝑏 = 𝑎𝑏
d) 𝑎× −𝑏 = (−𝑎𝑏)

4. Rules for division: a and b are positive numbers
𝑎
a) 𝑎÷𝑏 =
𝑏
𝑎
b) −𝑎 ÷ 𝑏 = − 𝑏
𝑎
c) −𝑎 ÷ −𝑏 = 𝑏
𝑎
d) 𝑎÷ −𝑏 = − 𝑏

5. Steps to perform computation involving combined operations:
I. Firstly, perform the operations in brackets
I . Secondly, perform operations of multiplication or division from left to right
I I. Finally, perform operations of addition or subtraction from left to right