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### Number and algebra

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# Double or Halve?

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### Let's Investigate Triangles

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Age 5 to 7

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We haven't yet received many solutions to this activity. If you notice anything interesting when you play this game, please email us with your ideas.

Joshua from Spring Hill Primary School in Australia had these ideas:

Q1: Does it matter if you go first or second? Why or why not?

It does not change any chance of winning.

Q2: Are there any particularly good numbers to choose as your target?

There are no specific numbers that are better to choose, it has the same likelihood.

Q3: What are you thinking about in order to try to win the game?

When you are close to the target number you should always half unless doubling can win it.

Good ideas, Joshua! I wonder why it might not matter if you go first or second?

Hannah from Oyster Bay Public School in Australia used a similar strategy:

I played this with my mum and these are some of the strategies that we did:

- We chose the number 82. I rolled first and doubled it.

- We both kept doubling our numbers to get to the number 82.

- We wrote the number rolled and the number doubled to keep track.

- We added each other's numbers.

- When we came close to 82 we started to half to make our number smaller.

- We skipped turns until we came up with a correct number that brought our number to our target number of 82.

- I won!

Well done Hannah! Thank you both for sending in your ideas.

Vincent and Tara are making triangles with the class construction set. They have a pile of strips of different lengths. How many different triangles can they make?