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This content is taken from the National STEM Learning Centre's online course, Maths Subject Knowledge: Understanding Numbers. Join the course to learn more.

Skip to 0 minutes and 7 seconds MICHAEL ANDERSON: So last week, we introduced the place value system and the base 10 number system.

Skip to 0 minutes and 12 seconds PAULA KELLY: OK. So using our base 10 number system, we’ve got here our table to show how we go from our Millions all the way down through Hundreds, Tens, and Units.

Skip to 0 minutes and 20 seconds MICHAEL ANDERSON: Yeah. So we can start with the right-hand side, our Units or our ones, and then each column gets 10 times larger– so the Tens, the Hundreds, Thousands, et cetera, et cetera.

Skip to 0 minutes and 29 seconds PAULA KELLY: OK. So using this number system, how could we express the number 18?

Skip to 0 minutes and 34 seconds MICHAEL ANDERSON: Well, it’s really important to make sure that we’re writing these in the right columns. So 18 stands for, well, 1 Ten and 8 Units. So I’m going to put just a 1 in the Tens column and an 8 in the Units or the Ones column.

Skip to 0 minutes and 47 seconds PAULA KELLY: OK. What about a large number?

Skip to 0 minutes and 49 seconds MICHAEL ANDERSON: So maybe 237? Well, it’s almost the way we say it. So we have 200. 30. Well, that’s 3 Tens. And then 7 is 7 Units.

Skip to 0 minutes and 59 seconds PAULA KELLY: OK. So let’s see what else we can do now with our whole number base 10 system.

Skip to 1 minute and 4 seconds MICHAEL ANDERSON: OK.

Grouping numbers

In this video, Michael and Paula recap the basics of how place value works in a base ten number system. With this fundamental understanding we can now look at how numbers are grouped.


In this task, we’d like you to think about how numbers can be grouped in many different ways. We’ll use Padlet, a virtual pinboard, as a way for you to share how you’ve grouped your numbers should you wish. Guidance for using Padlet.

  1. Get 10 pieces of paper or sticky notes.
  2. On each piece of paper write a positive whole number. These can be any positive whole number, not necessarily in any order.
  3. Look at the numbers and group the numbers in some way, so that all numbers in a group have the same property.
  4. Label these groups up and then, if you wish, take a photo of your groupings to share on the Number Groups Padlet.


How did you group your numbers? Did you have an unusual group, an interesting group or a group no one else will have thought of?

Put your photos on the Padlet and post your comments below.

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This video is from the free online course:

Maths Subject Knowledge: Understanding Numbers

National STEM Learning Centre