1. Solving Simple Algebraic Equations

2. The equals sign does not mean “solve it”
Look at it. = There are 2 lines going both ways. It is all about balance.

3. Look at these signs
≈ - This sign means “approximately”. Not exactly right, but very close.
≠ - This sign means “not equal to”. It means that the equation is not balanced, the answer is wrong.
50 ÷ 3 ≈ 16.5
3 x 7 ≠ 41
So, = means exact balance and harmony on both sides.

4. Some true equations 30 + 20 = 100 ÷ 2 100 – 81 = 19 19 = 10 + 9
5 x 5 = 25
6 x 3 =
90 ÷ 10 = 3 x 3
= 100 ÷ 2
100 – 81 = 19
19 =
You get the message? Equals symbolises balance.

5. Is this balanced?
NO!!!

6. Is this balanced?
NO!!!!

7. OK Miss. We’re not in primary school!
The total number of students in this room is n.
The students are made up of boys and girls.
So, would I be right if I said n = b + g?
Write down that formula!
n = b + g

8. Let’s see what we can do with this formula
If I know two of these variables, I can find out the other one.
If I know the number of boys and girls, I can find n.
Like wise, if I know the total (n) and the boys, I can find the number of girls.
n = b + g
g = n – b

9. Lets say there are 12 students

10. Girls & boys
5 x
7 x

11. 12 = 7 + 5
n = b + g =

12. Rearranging the formula
The formula can be rearranged to find the number that I want to find.
I worked this out using inverse operations! =

13. Inverse operations n = b + g So, rearrange.... 12 – 7 = 7 – 7 + 5
12 = 7 + 5
What is the opposite of +7?
-7 
So, rearrange....
12 – 7 = 7 – 7 + 5
Simplify....
12-7 = 5

14. = - = + - - =