A short instructional transcript by Florence (YouTube) explaining decimal place value to the thousandths (three decimal places). It teaches how to read and write decimals (example: 0.352), how to use a place-value chart to identify tenths, hundredths and thousandths, and how to compare decimals using column-wise comparison to correct the misconception that more digits means a larger value (example comparison: 0.352 vs 0.37).
Chapters
Hi, I'm Florence, and today we're going to look at reading, writing and comparing decimal numbers with up to three decimal places. Now, in a previous video, we've looked at tenths and hundredths and explored how you can show children what that place value looks like. But in order to compare numbers with up to three decimal places, they're also going to need to have an understanding of thousandths. The thousandths sit immediately to the right of the hundredths column. And so we know that there are 10,000ths in a hundredth. If we look at a pictorial representation of that, we can see that our ten thousands make up one hundredth. So let's have a look at how we would write one of these decimal numbers. Here I have 0.352, and I'm going to use my place value chart to help me look at the place value of each of those digits. I have no ones. I have 3/10, 5/ths and 2,000ths. Now, a common misconception when pupils ask to compare decimal numbers is to assume when a decimal number has more digits, it's going to be larger. But that's not always the case. So again, using our place value chart is a really good way to address this misconception. Let's compare 0.352 with 0.37. When using the place value chart with pupils, just as you would with a whole number, encourage them to start at the place value column with the largest value and work their way along comparing the value of the digits. Both these numbers have no one, so we need to move to the next column. They both have three tenths, so again, we're going to need to look at the next column along. We can see here that this decimal has five hundredths, whereas this one has seven hundredths. So ask pupils which is bigger, five hundredths or seven hundredths, and they can even use base 10, perhaps, to show you that seven hundredths is bigger. So 0.37 is the larger decimal. So there you go. Hopefully that gives you an idea of how you can help address the misconceptions and support pupils when comparing decimals with up to three decimal places.
