Strike it out! Let's play

OK, I'm joined here with Barbara today. Hi Barbara!

Hi Michelle!

And we wanted to play strike it out, but have you played this game before?

I haven't. Will you teach me?

I sure will! Now the first thing that we need to play is a number line as our game board for this game. So, if I do this...it's got quite a bit of a bump in it but it doesn't matter. It goes from zero to 20. But we need to fill in all the other numbers. Well I've got an idea. Yeah. If you look around the middle you might be able to put 10. That's a really good idea because ten is halfway between zero and 20.

And then we could use the same strategy, so from zero to 10, half-way would be five. Yeah, and then half-way between 10 and 20 you have 15. Yeah, so that's about halfway there. Do you agree? Yep.

And then we would need to fifth these components. I don't think I know how to fifth because we can't halve it. Well, I learned this strategy from a Professor, Professor Di Sieman. She showed us this strategy about getting your eye in. So she said you just sort of need to move your finger along until you can start to see that if I halve this section, and halved it again, would that be about the same distance as my finger has moved here?

Oh, ok! Yeah, so if I move my finger and say this is about half here and if I halve that again, it would be back there so, now, I could say they are now about the same. So if I go, that's about right for my 1-fifth and then if I halve this and then halve these portions, well, it's a bit wonky on this side, but it's not bad for estimating, and then I can fill it in.

Do you want to have a go?

I'm trying to imagine where the 6 would be and then I'm halving and halving again and seeing if that's about the same. Yeah! Pretty happy with that actually.

So then I can halve this and halve it again. And then I can put 6, 7, 8, 9. Yeah! Because they're the numbers between 5 and 10. Here, you fill out the numbers between 10 and 15.

OK, so I'll do the same thing. I'm still happy with that. OK and then half way, and then half again. It's a little bit wonky, but that doesn't matter, does it?

No, because we're estimating. OK, actually that's pretty good. Yeah! Alright, I'll do the last one. I reckon about there...

And the numbers between 15 and 20 or 16, 17, 18 and 19.

Alright, we're ready to play! So this is how you play. You can be blue, I will be orange and you just pick any 2 numbers that you'd like to make a number sentence with, or an equation. So if for example you could say 1 + 2 is 3 or 5 - 4 is 1. We use addition and subtraction. So what are you thinking you might like to start with, and I'll show you how to record it.

OK, so I'm thinking...um... maybe...10 + 5 is 15. Awesome, so you cross out the 10, or strike it out, strike out the five and circle the 15.

OK.

And it's equivalent value to 15 so I can circle that one. So then you just need to record your move here. OK. I'm joining 5 and 10 and that's equivalent in value to 15. Yeah. And so now I have to use the 15, and I have to see if I can use addition or subtraction as well. I can't do something like 20 - 15 is 5 because the five has been used. So I can only use unused numbers. I could do something like 15 - 14 is 1. I could do something like 15 + 4 is 19. And I'm going to record my turn here.

15 combined with 4 is equivalent in value to 19... and now you have to use the 19!

Your go!

OK, so... I start from 19 and I strike it out then I can subtract 17. Yeah, the answer is two because 19 take away 17 is 2.

And now you need to start from 2! Yes! And the way you win is to be the last person that can record a go (or a turn). OK, so I can eventually try to block people. So I can think about being tricky? Yes, you can!

Good! Because I like being tricky! So do I! [laughter]. Ok, so I'm going to say 2 + 7 is 9.

So, 2 combined with 7 is equivalent in value to 9. Ok, your turn.

Alright, so I'm at nine.

Ooo, 20 still available, isn't it? OK, so I'm going to combine 9 and 11, for a total of 20.

Ok. I still think there's....I'm trying to be strategic, but I still think there's maybe too many numbers for me to plan out too far. So, I'm going to say... 20 subtract 14 is equivalent to 6. So 14 minus 20

Ooop, start again. 20 minus 14 is equivalent to 6.

Your turn 6...and....

Oooo, I just need some thinking time.

Of course. We can work together too, if you want. What are you thinking?

Do I trust you?

I think I want to use some of these numbers up here, so I think... oh yeah, there's a way. So I want to go up from 6...

So, I'm thinking 12 could work.

Because if I combine 6... and 12...then it's equivalent to 18.

Now this is going to be tricky I think for me because from 18, I only now have 16, 13, 8, 3, 1 and 0 left.

So if I did 18 - 1 that would be 17 which is in use.

18 - 16 would be 2 which has been used. 18 - 13 would be 5. That means 18 - 8 would be 10. It's been used .If I did 18 plus anything, it makes it bigger and so there's no options for me.

Which means I think you might have won! Ooo, beginners luck! Can you see anything?

I wonder if anybody out there who's joining us can see anything.

So over to you guys... is there a way that I could possibly win? Or has Barbara got this one? and I think I want to play this game lots of times because I think the more I play it, the more strategic I can be in, the more I can trap you because I kind of trapped you by accident [laughter].

Alright, have fun!