What you need to know

Things to remember:

  • If we add to an x we do a subtraction.
  • If we subtract from an x we do an addition.
  • If we multiply and x we do a division.
  • If we divide and x we do a multiplication.
  • We are trying to get the xon its own.

When we rearrange in maths, it just means to move things around. If we rearrange for something, like x, this just means we are trying to get it by itself.

Rearrange the equation to get x on its own:

x + 3 = 12

Let’s think about what this is saying. This tells us that something, x, plus something is equal to 12. Well, that is pretty easy, we know that we have to add 3 to 9 to make 12.

x + 3 = 12

9 + 3 = 12

So, x must be 9. x=9 But, how could we write the equation we start with so that x was by itself? Well, let’s just get ride of that 3.

x = 12

But, wait, we said that x=9 not 12. So, how can we make the 12 into a 9? We subtract 3.

12-3=9

So, let’s rewrite x=9

x = 9

x = 12-3

Now, let’s compare this with the equation we started with.

x + 3 = 12

x = 12-3

So, all we did was move the number to the other side and did the opposite of addition, subtraction! This is how we get x for other questions to, we just move the number over and do the opposite.

Rearrange the equation to get x on its own:

x -17 = 12

x = 12+17

Rearrange the equation to get x on its own:

x \times4 = 16

x = 16\div4

Rearrange the equation to get x on its own:

x \div9 = 4

x = 18\times4

Example Questions

Question 1: Rearrange the equation to get x on its own:

x \times12 = 36

Answer

x = 36\div12

Question 2: Rearrange the equation to get x on its own:

x \div7 = 1

Answer

x = 11\times7