## Maths Starter Shed 3

## Cross a River - Medium Riddle

A couple of maths tests taken from recent newspaper articles.

## I'm a Celebrity Maths Challenge.

The poor old I am a Celebrity contestants are given a maths problem to solve, the answer then allows them to open the chest.

Can you solve it before they do?

5 + 7 = ? X 12 = ? - 52 = ? X 11 = The final answer.

Can you solve it before they do?

5 + 7 = ? X 12 = ? - 52 = ? X 11 = The final answer.

## Prison Guard Question

Not completely mathematical this problem, but very logical. Had me scratching my head for some time. Interesting to throw the problem at upper Keystage 2 / Keystage 3 children to see what they can come up with.

## Mind Reading.

Lots to think about with this, get your children to run through the sequence solving the different maths problems, then trying to work out how they get the prediction right.

- The secret is that you will always end up with 4 when you subtract by 5. Thus, giving you 4=D. That will most likely cause the person to pick Denmark. It will not ALWAYS happen, but there is high probability you'll get Denmark, orange, kangaroo.

## How Predictable Are You?

A trick whereby the presenter predicts which symbol you will finish on with a series of moves. Have a go and try to work out how he does it.

Below is a video by the excellent James Grime that tells you just how it works.

Below is a video by the excellent James Grime that tells you just how it works.

## Where Does the Extra Man Come From?

This is very similar to the chocolate trick that Rob posted on the home page. This involves 12 men that magically become 13. Lots of points for discussion with children sharing ideas of how it may happen.

## Why Maths is Important.

A very cool video, suited more for older children.

Could be quite open ended, ask your children, what this has to do with maths.

Gather ideas and look at the operations needed to perform such a stunt.

Distance, measuring, angles, friction, wind speed etc.

Could be quite open ended, ask your children, what this has to do with maths.

Gather ideas and look at the operations needed to perform such a stunt.

Distance, measuring, angles, friction, wind speed etc.

## Towers of Hanoi - Dara O Briain

This is a new take on the old Tower of Hanoi challenge, involving tins of Baked Beans.

Stop at 1:07 and answer the question, "How many times do we have to move the tins?"

At 2:10 stop again, ask the children if you think they solved the problem in the minimum amount of moves and why.

3:10 predict again, how many moves will it take to get three across.

Look at the pattern, stop if you want and explain what is being shown, then when they offer the challenge of 64 tins and how many moves it would make, try and work it out. You may want to start at a lower number and build up.

Stop at 1:07 and answer the question, "How many times do we have to move the tins?"

At 2:10 stop again, ask the children if you think they solved the problem in the minimum amount of moves and why.

3:10 predict again, how many moves will it take to get three across.

Look at the pattern, stop if you want and explain what is being shown, then when they offer the challenge of 64 tins and how many moves it would make, try and work it out. You may want to start at a lower number and build up.

## The Magic Monkey.

This is a fantastic little maths brain teaser, that can be used in different ways throughout Keystage 1 and 2

Click the picture above to go to the website.

The Magic Monkey takes you through a series of maths problems before showing the symbol that matches your final number.

In year two we have used it to look at what a 2 digit number is, for addition problem solving and subtraction and for number recognition. It is amazing the ideas that the children have on how the Magic Monkey manages to get the symbol right each time. We have had to whisper, write down our numbers and even shout red herring numbers to try and trick our magic friend.

A colleague in Year 5 and 6 has used this as a challenge to his children, to try and work out how the Magic Monkey solves the problem each time.

Click the picture above to go to the website.

The Magic Monkey takes you through a series of maths problems before showing the symbol that matches your final number.

In year two we have used it to look at what a 2 digit number is, for addition problem solving and subtraction and for number recognition. It is amazing the ideas that the children have on how the Magic Monkey manages to get the symbol right each time. We have had to whisper, write down our numbers and even shout red herring numbers to try and trick our magic friend.

A colleague in Year 5 and 6 has used this as a challenge to his children, to try and work out how the Magic Monkey solves the problem each time.

## Paper Folding Challenge - Mythbusters

This video is based on the challenge that no matter how big or small a piece of paper you have, you cannot fold more than 7 times. Of course the Myth Busters have to go that little bit further to try and bust the myth.

A great challenge to do with children of any age.

If you have a normal sheet of notebook paper and you try to fold it in half multiple times, you probably cannot get it to fold more than 6 times. Maybe 7 if you are really strong. That maximum limit is caused by two things:

1) The number of layers of paper doubles with each fold. So you start with a single layer, then you have two layers, then four, then eight, then 16, then 32, then 64 layers after six folds. Maybe if you are very strong, and you use a pair of pliers, you can get to seven folds and 128 layers, but it probably won’t be pretty.

2) At that point the sheet of paper is so small, and the number of layers so large relative to the small size, and the distortion caused by the folds so great, that there is no way to fold it again. You can’t apply enough leverage, and the fibers of the paper do not have enough flexibility for another fold.

But what if you used a much larger piece of paper, so that you can diminish the effects of fold distortion and paper fiber flexibility? If you use a big enough sheet of paper, you can get to 11 folds, or 2,048 layers, before you reach the limitations of folding

A great challenge to do with children of any age.

If you have a normal sheet of notebook paper and you try to fold it in half multiple times, you probably cannot get it to fold more than 6 times. Maybe 7 if you are really strong. That maximum limit is caused by two things:

1) The number of layers of paper doubles with each fold. So you start with a single layer, then you have two layers, then four, then eight, then 16, then 32, then 64 layers after six folds. Maybe if you are very strong, and you use a pair of pliers, you can get to seven folds and 128 layers, but it probably won’t be pretty.

2) At that point the sheet of paper is so small, and the number of layers so large relative to the small size, and the distortion caused by the folds so great, that there is no way to fold it again. You can’t apply enough leverage, and the fibers of the paper do not have enough flexibility for another fold.

But what if you used a much larger piece of paper, so that you can diminish the effects of fold distortion and paper fiber flexibility? If you use a big enough sheet of paper, you can get to 11 folds, or 2,048 layers, before you reach the limitations of folding