How To Divide

How To Divide
With A Number Line

Most adults know how to divide, but just as with fractions, explaining it to a child can be tricky.

For these simple divisions, we will use a positive number line starting at zero. The negative numbers are left out to make it clear that the division sum starts at zero. Zero is the starting point of all division sums, just as it is the starting point of all sums.

Take the sum 12 divided by 4. While the answer is quite obviously 3, this is not obvious to the child who has not yet mastered multiplication and division. So how do we solve this problem visually in a consistent manner that is clear to the child’s mind?

First we get a number line and count on it from zero up to 12, which is 12 steps in total.

Now 12 represents that chunk of the number line, so we can also draw it as a colored band. A highlighter pen is ideal for this task.

Secondly, starting at the zero again, we break the colored bar into chunks of three:

number line division

And so we end up with 4 complete chunks. The answer is 4.

Confirm It With Blocks

This method can be confirmed by placing 12 cubes in a line and splitting the line up into lots of three. Doing so confirms the number line work and also lets your child repeat the sum with her hands. This brings other senses into the process and helps to strengthen the concept.

Resources

For a sheet of number lines exactly the same as those used on this page, click here. This is a PDF file that you can print or save to your computer, and it is free for your personal use.