Find 10, 100, Or 1000 More Or Less Than A Given Number

Hi, I'm Ellie and in this video we're going to be looking at adding or subtracting ten hundred or one thousand from any given number. So the number that we're starting with today is 2047. Now, when we're doing this, it's really important that your pupils understand the value of each digit and that's why a place value chart like this is really useful. You can have it on a whiteboard or children can have their own at their desk. So here I've represented our number 2047 on our place value chart. I've got 2000s, no hundreds, our four tens and seven ones. So the first thing that we're going to do is look at what happens when we add 10. So this is quite simple. We're simply adding another 10 to our tens column. So rather than 2,047, we've now got 2000s still zero, hundreds, five tens and our seven ones are the same. A really good thing to do whilst you're looking at a place value chart is also look at a number line. So here I've got a blank number line. I'm going to place 2047 here and we're going to show people what happens when you add a 10. So I'm simply going to do one jump to add 10 and our number will change to 2057. So a good way to help people start to spot patterns is to ask them to look at these numbers and say, what has happened to the number? So hopefully they'll see that it's this digit in the tens place which has changed. When we've added 10, the next thing we're going to do is look at what happens when we subtract 10. So I'm going to go back and start with our number 2047. But this time we're taking away 1 10. So we remove a 10 from our tens column, which means that we've got 2000, 0 hundreds, 3 tens and 7 ones. So now we've got 2000 and 37 again, we can go back to our number line to help reinforce the value of what's happening with the numbers. But this time we're taking away 10. So the number underneath here is going to be 2037. Again, ask the people what's happened to the numbers and we can see that it's this digit here which has changed. So we've got 2,037 again. You can follow the same process, but for adding hundreds. So this time, what happens if I add 100 to my number? I'm going to put an extra hundred in that column there. So this time our number is 2147. And if we return to our number line, that's where you can show a larger jump to reinforce that, you're adding 100. So rather than just adding 10, I'm going to do a much bigger jump, go all the way up here, Label this as adding 100 and the pupil should be able to see that you're getting to 2147. The bit where it might get a bit trickier is if you're taking away 100 from our starting number. So if we go back to starting with 2047 and I want to take away 100, pupils might get a little bit stuck because there's no hundreds here. So what do they need to do? In this instance, all you need to do is exchange one of your thousands for ten hundreds. So we're going to swap this over and we're going to put 10 hundreds into our hundreds column. This is a really important skill to teach pupils about regrouping. And we've got 1000 is the same as 10 hundreds. And this time they should be able to see what happens to the number. So I've got 1000, my 10 hundreds, and I'm just going to take one of those away. So we asked them to represent this number. We've got 1000, we've got 9 hundreds, we've still got 4 tens and we've got 7 ones. So the number that we get to is 1947. And the final thing we'll do is just count back 100 to represent this on our number line. So taking away 100 will give us 1,947. And that's what you can do to practice adding and subtracting tens, hundreds and thousands with your pupils.