Subitising

Before we get started, make sure you've got some dried pasta or blocks or counters, a table or an area that you can work on, and your speedy eyeballs at the ready. If you don't have those things just yet, just click pause, go find them and then come back and play the video again. See you soon.

Hello there little mathematicians, I hope you're having a really lovely day today. Today we're going to practise around with our skills at subitising and that means that when we can look at something and see how many there are without having to count. So for example, if I put this many pieces of pasta out, how many can you see? Two, yeah, I can see two as well and I didn't have to count them and so when this happens to me it's called subitising. And so what we're going to do today is I've got some plates over here that have things like counters and dice patterns on them and I'm going to show them to you really quickly and turn it over, and then we're both going to have a turn of trying to imagine what it was that we saw on the plate and recreate it here. You can use counters or blocks or pieces of pasta, even toys that you like. I'm gonna use pasta today to help me make these representations, and then we're going to turn our plate over again and check to see what happened. So if your little eyeballs are ready, we can get started. Are you ready? Excellent!

So here comes the first one and I think you've already seen it, but have a look. OK, and now think about how many did you see and how did you see it? And let's try to recreate it. So I'm going to cover this up so that I don't disturb your thinking. I think I saw that many, and I think, it looked a bit like that, let me think. Yeah. Can you show me your representation? Let's see if we were thinking the same. This is what I was thinking about. I think I saw three because in my mind I could imagine seeing two and one more, and I know two and one more is three, but let's check and see exactly what I saw. Let's check. Is it three? Yeah 'cause here's two or two and one more, we could count them all to check 1, 2, 3. So I have 1, 2, 3 counters. The pasta and you had that too? And I did see two together and one more. But actually these ones are a bit closer. So if I was really being really precise, my representation would have looked a little bit more like this, where these ones were close together and this one was further away, but I was still able to see three.

Should we have another go together? Excellent! Put this one away. I'll take my pasta away. Here we go. Fast eyeballs ready? What are you thinking? How many did you see and how did you see it? OK, I'll put a picture in my brain and now I'm gonna recreate it as well, and let's see if we were thinking the same or seeing the same. Oh one? Is that what you saw too? Let's check. It is one and this one looks like one on a dice, doesn't it? Because of the square outline.

OK, let's see. Here comes another one. Eyeballs ready? Good job. OK, how many did you see this time? I'm going to make my representation. While, you make yours. OK, are you ready? I imagined it in my brain and what I thought I saw was a triangle and one dot in each of the corners of the triangle and I know a triangle has three corners and so I made my representation look like this. Yours was similar? Shall we check? Ok, let's see, huh? There we go, three! 1, 2, 3 in a triangle shape, 1, 2, 3 like a triangle.

OK, let's try another one. Eyeballs ready. OK, here we go. Over to you now take a picture in your brain. Think about what you saw and then try to recreate it. I'm going to do the same. See. OK. What did you think you saw? Some of us are thinking about similar things. I also thought I saw a square, but I thought it was twisted on its side a little bit and I saw a square, but actually some of the counters were one colour and there was one down the bottom. I think that was a different colour and so when I used my pasta shells, I made it like this so that I could see that it's a square just twisted slightly. See if I turn it this way, it looks like a square. And this way it's still a square 'cause there were four corners. And this one I did upside down to try to show that I think there were three green ones. I think and one that was maybe pink or purple. Did you see that too? Let's have a look ready. Oh, did you have that also? Yeah, and you know pasta is really tricky in this case because usually it only comes in one colour and if I had different coloured pasta, I would sometimes like to be able to show that in a different colour, but you might have had it like this as well because you saw four and this is also a really good way of thinking 'cause what this shows us in this representation is four, is made up of three and one more and we see that really obviously and this one just shows us four as one clump of four, and if I spin it this way, it just looks like four on a dice pattern that's just gone a little bit wonky, so I can still trust that it's four.

Alright, shall we try one more together? Ok, let's do it. Clear away these things. Let's go. Are you ready? Ok, I hope you took a picture in your brain and you're imagining now how many you saw and then on with your equipment. Now try to recreate it. OK, I'm going to do the same. Let's see. I think I saw it like that, but I'll need that. OK, what were you thinking when you saw that representation? Ah, I can hear it. Different ideas. Some of you were thinkingthat you saw four on a dice pattern and one more, and that's what you imagined. Someone else was saying that they think they saw three - 1, 2, 3, and another two. Yeah, and that's how I saw it. I thought I saw it like six - 1, 2, 3, 4, 5, 6 but one was missing. And so what I was thinking of doing was to show a piece of pasta there, that then went away so, let's have a look. Huh, yeah, so we could see 1, 2, 3, 4 like a dice. Cover this up. That looks like four on a dice. And then the one more. Or you might have seen the three first. See the three and then the other two. Yeah, or this idea of one more being here, which would have been six and if I get rid of it, the number before six is five. Oh, that's a really good way of thinking, that idea that actually you could have moved this dot down here to have made five like a dice pattern. Really nice thinking mathematicians and really nice subitising!

So what was the mathematics today? So what we realised is that when we subitise, that means we can work out how many there are without having to count everything we see. We also know that visualising helps us build our mathematical imaginations, and that exploring how different people use subitising and other knowledge they have to work out how many there are in a collection, helps us learn different things about numbers. So, just by looking at that collection of five today, Cate helped us see that five is made up of three and two. James helped us see that five is made up of four and one and Michelle helped us see that five is one less than six. This is really important as we get older as mathematicians so that we can learn to use numbers flexibly. Nice work today guys!