Introduction to Algebra  Multiplication
Please read Introduction to Algebra first
Another Puzzle
What is the missing number?
The answer is 2, right? Because 2 × 4 = 8.
Well, in Algebra we don't use blank boxes, we use
a letter. So we might write:
But the "x" looks like the "×"! ... that could be very confusing ... so in Algebra we don't use the multiply symbol (×) between numbers
and letters, we simply put the number next to the letter to mean multiply:
You would say in English "four x equals eight", meaning that 4 x's make 8. And the answer would be written:
How to Solve
On the previous page we showed this neat stepbystep approach:
 Work out what to remove to get "x = ..."
 Remove it by doing the opposite
 Do that to both sides
It still works, but you have to know that dividing is the opposite of multiplying. Have a look at this example:
We want to remove the "4" 
To remove it, do the opposite, in this case divide by 4: 
Do it to both sides: 
Which is ... 
Solved! 





Why did we divide by 4 on both sides?
Because of the need for balance ...

Divide Left by 4 
Divide Right by 4 Also 



In Balance 
Out of Balance! 
In Balance Again 
Just remember ...
To keep the balance, what you do to one side of the "="
you should also do to the other side! 
Another Puzzle
Solve this one:
Start with: 
x/3 = 5 

What you are aiming for is an answer like "x = ...", and the divide by 3 is in the way of that!
If you multiply by 3 you can cancel out the divide by 3 (because 3/3=1)




So, let us have a go at multiplying by 3 on both sides: 
x/3 ×3 = 5 ×3 


A little arithmetic (3/3 = 1 and 5×3 = 15) becomes: 
1x = 15 


Which is just: 
x = 15 

Solved! 
(Quick Check: 15/3 = 5) 

Have a Try Yourself
Now practice on this Algebra Multiplication Worksheet and then check your answers on the page after. Try to use the steps we have shown you here, rather than just guessing!
More Complicated Example
How would you solve this?
It might look hard, but not if you solve it in stages.
First let us get rid of the "+2":
Start with: 
x/3 + 2 = 5 


To remove the plus 2 use minus 2 (because 22=0)

x/3 + 2 2 = 5 2 


A little arithmetic (22 = 0 and 52 = 3) becomes: 
x/3 + 0 = 3 


Which is just: 
x/3 = 3 
Now, get rid of the "/3":
Start with: 
x/3 = 3 


If you multiply by 3 you can cancel out the divide by 3:

x/3 ×3 = 3 ×3 


A little arithmetic (3/3 = 1 and 3×3 = 9) becomes: 
1x = 9 


Which is just: 
x = 9 

Solved! 
(Quick Check: 9/3 + 2 = 3+2 = 5) 

When you get more experienced:
When you get more experienced, you can solve it like this:
Start with: 
x/3 + 2 = 5 
Subtract 2 from both sides:

x/3 + 2 2 = 5 2 
Simplify: 
x/3 = 3 
Multiply by 3 on both sides:

x/3 ×3 = 3 ×3 
Simplify: 
x = 9 
Or even like this:
Start with: 
x/3 + 2 = 5 
Subtract 2:

x/3 = 3 
Multiply by 3:

x = 9 
Have a Try Yourself
Now practice on this Algebra (Two Steps to Solve) Worksheet and then check your answers on the page after. Try to use the steps we have shown you here, rather than just guessing!
