Subtraction for Kids | How to Subtract | Number Lines | KS1 | Math Games | Subtraction Games KS1

Welcome to Learning Mole. This is lesson 7 in our series Subtraction for Kids and at this stage we're going to move on to Key Stage 2 so that's sort of between 8 and 11 year olds and stage and we're going to think about now your child will be facing a little bit more complex subtraction calculations and we're going to be thinking about using number lines as a tool. Now I am a big big fan of empty or blank number lines solely for the reason that they can actually go to suit whatever calculation you want. If you're restricted to certain numbers it's not always useful to be able to use a number line so I'm just going to talk you through how you might want to provide your child with an empty number line and how they might actually find it useful. Again it's all back to that visualising the numbers so that they're able to then move from this idea of a blank number line into actually being able to do this mentally and it's about giving them the understanding of what they're actually doing. So for something like a calculation which is 63 take away 7 yes your child might be able to do that in head which is great but if your child is still struggling especially with crossing that tens barrier you want to actually maybe give them something visual like this. So how an empty number line works is you basically draw a line and then you put your number that you want to start with. I would always encourage you to use the end of the line to reinforce the idea that subtraction actually is counting backwards so you will put your biggest number at the end of your line and then it's just a case of jumping backwards so you can either have the numbers on there before which is absolutely fine or you can put the numbers on as you go along. So I'm just going to put the numbers on for ease of use so I'm going to do 63, 62, 61. It's also a really good lesson in helping your child count backwards if they're still struggling with these sort of upper numbers and when they're actually putting their numbers on their number line it actually will really help them with that counting as well. So I put my numbers on and so I know I've got my 63 it's on there and I actually even get my children to underline the number they're working with and check that it's on there first and then they're counting back in seven. That means that they're not mixing up those numbers so I know I've already done this now I need to do this I need to take away my seven so starting at 63 and counting back seven. One, two, three, four, five, six, seven. My answer is 56. I double check. One, two, three, four, five, six, seven and I know my answer is 56. So really really clear visual for your child and no resources necessary. If your child needs to work this out somewhere if they're in school or if they're basically anywhere when they have a pen and paper they've got a resource with them which is always great. Your child may also then be faced with something that's a little bit more tricky that's not just a single digit they're now taking away a double digit or a two digit number and this is where we talk about bridging through ten where they can actually start to bring in their counting steps as well so that they're not counting back. Number lines are not really designed for counting back 19 steps. As you can imagine if you're counting back 19 there are loads of chances for error in there so this is not really what we would be wanting to use this for. We would be wanting to actually use this in two steps of 10. So what we might be saying is that again your 47 goes at the end of your number line. You're underlining it to say you've done it and we need to come back and we need to count back 19. So what you might be saying to your child here is well could we split this number up? Could we partition this number? You might hear your child talking about partitioning. Partitioning just means breaking the number up into its tens and its units. So could we partition this number into tens and units? It's got nine units and it's got one ten. Very very important that you actually write down that this is ten and it's not one. So again it's something you need to remember. So we already know that we can count in steps of 10 so could we just take away 10 straight away rather than having to do 10 jumps and your child will already say yes I can do that. So we do one big jump of 10, take away 10 and they should be able to tell you that's 37. And then they can take away their nine jumps. Again if you want to prepare your number line before or you can do the numbers after it's not a problem. I think it's sometimes easier just to do your numbers as you go along. Okay so then you're going to jump back so your nine. So you've got one, two, three, four, five, six, seven, eight, nine and you've got to your answer 28. Your child may also tell you here that actually I could jump back 10 and add one back on. That's brilliant because they're really starting to think mentally and actually putting that into practice which is great. But I'm just going to do another one of these for you because they can be really quite tricky especially if you've not done it before with your child. So let me just talk you through just one more just to give you an idea. I'm just going to draw a rough number line in here because you don't always have a ruler at hand. So this time I'm going to do 73, take away 24. Okay so I put my 73 up, underline it or circle it or something to say I've done it. I need to take away to my 24. This is where I partition into my tens and units. I know that there's four and I know that there's 20. I can even write it like that so that it's really really clear. 20. I can jump back 20 or I can jump back two tens. It might be easier for your child to jump back in 10 which is 53 and then jump back there for 1, 2, 3, 4, 53, 52, 51, 50, 49. So it's just a really nice tool. Not all children will love it but it's a nice tool for children that do like working in a number line and sometimes need that wee bit of reassurance and need that wee bit of security. Sometimes children will do that mentally but then they'll need that little security just for double checking. So it is a really really nice resource and really does help your child think about subtracting and actually get that concept of going backwards and counting backwards.