# Video List

### The Best Card Trick?

##### Age 11 to 16 Challenge Level:

Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?

### Take Three from Five

##### Age 14 to 16 Challenge Level:

Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can they stop him?

##### Age 14 to 16 Challenge Level:

A picture is made by joining five small quadrilaterals together to make a large quadrilateral. Is it possible to draw a similar picture if all the small quadrilaterals are cyclic?

### Amazing Card Trick

##### Age 11 to 14 Challenge Level:

How is it possible to predict the card?

### Seven Squares - Group-worthy Task

##### Age 11 to 14 Challenge Level:

Choose a couple of the sequences. Try to picture how to make the next, and the next, and the next... Can you describe your reasoning?

##### Age 14 to 16 Challenge Level:

Can you find out what is special about the dimensions of rectangles you can make with squares, sticks and units?

### Always a Multiple?

##### Age 11 to 14 Challenge Level:

Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...

### Whirlyball

##### Age 16 to 18 Challenge Level:

Whirl a conker around in a horizontal circle on a piece of string. What is the smallest angular speed with which it can whirl?

##### Age 7 to 14 Challenge Level:

Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?

### Symmetric Tangles

##### Age 14 to 16

The tangles created by the twists and turns of the Conway rope trick are surprisingly symmetrical. Here's why!

### ACE, TWO, THREE...

##### Age 11 to 14 Challenge Level:

Can you picture how to order the cards to reproduce Charlie's card trick for yourself?

### Twisting and Turning

##### Age 11 to 14 Challenge Level:

Take a look at the video and try to find a sequence of moves that will untangle the ropes.

### The Invertible Trefoil

##### Age 14 to 16 Challenge Level:

When is a knot invertible ?

### Impossible Square?

##### Age 16 to 18 Challenge Level:

Can you make a square from these triangles?

### Turning Granny

##### Age 7 to 11 Challenge Level:

A brief video looking at how you can sometimes use symmetry to distinguish knots. Can you use this idea to investigate the differences between the granny knot and the reef knot?

### Impossible Triangles?

##### Age 16 to 18 Challenge Level:

Which of these triangular jigsaws are impossible to finish?

### Galley Division

##### Age 14 to 16 Challenge Level:

Can you explain how Galley Division works?

### Strike it Out

##### Age 5 to 11 Challenge Level:

Use your addition and subtraction skills, combined with some strategic thinking, to beat your partner at this game.

### Speedy Summations

##### Age 16 to 18 Challenge Level:

Watch the video to see how to add together an arithmetic sequence of numbers efficiently.

### Slick Summing

##### Age 14 to 16 Challenge Level:

Watch the video to see how Charlie works out the sum. Can you adapt his method?

### Modular Origami Polyhedra

##### Age 7 to 16 Challenge Level:

These models have appeared around the Centre for Mathematical Sciences. Perhaps you would like to try to make some similar models of your own.

### Kingsfield School - Building on Rich Starting Points

##### Age 5 to 18

Alf and Tracy explain how the Kingsfield School maths department use common tasks to encourage all students to think mathematically about key areas in the curriculum.

### Drawing Celtic Knots

##### Age 11 to 14 Challenge Level:

Here is a chance to create some Celtic knots and explore the mathematics behind them.

### Turning the Place Over

##### Age 11 to 18 Challenge Level:

As part of Liverpool08 European Capital of Culture there were a huge number of events and displays. One of the art installations was called "Turning the Place Over". Can you find our how it works?

### How Many?

##### Age 5 to 7 Challenge Level:

This project challenges you to work out the number of cubes hidden under a cloth. What questions would you like to ask?

### Introduction to Number Plumber

##### Age 7 to 18 Challenge Level:

Video showing how to use the Number Plumber

### Jo Boaler Explains Complex Instruction

##### Age 5 to 18 Challenge Level:

A video clip of Jo Boaler talking about Complex Instruction.

### Dotty Six

##### Age 5 to 11 Challenge Level:

Dotty Six is a simple dice game that you can adapt in many ways.

### Bryony's Triangle

##### Age 7 to 11 Challenge Level:

Watch the video to see how to fold a square of paper to create a flower. What fraction of the piece of paper is the small triangle?

### Take One Example

##### Age 5 to 11

This article introduces the idea of generic proof for younger children and illustrates how one example can offer a proof of a general result through unpacking its underlying structure.

### Constructing Triangles

##### Age 11 to 14 Challenge Level:

Generate three random numbers to determine the side lengths of a triangle. What triangles can you draw?

### James's Code Challenge

##### Age 7 to 18 Challenge Level:

The Enigma Project's James Grime has created a video code challenge. Watch it here!

### That Number Square!

##### Age 5 to 11 Challenge Level:

Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?

### Summing Consecutive Numbers

##### Age 11 to 14 Challenge Level:

15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?

### Angle Trisection

##### Age 14 to 16 Challenge Level:

It is impossible to trisect an angle using only ruler and compasses but it can be done using a carpenter's square.

### Beelines

##### Age 14 to 16 Challenge Level:

Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?

##### Age 11 to 16 Challenge Level:

The items in the shopping basket add and multiply to give the same amount. What could their prices be?

### Totality

##### Age 5 to 11 Challenge Level:

This is an adding game for two players.

### Frogs

##### Age 11 to 14 Challenge Level:

How many moves does it take to swap over some red and blue frogs? Do you have a method?

### Counting Cards

##### Age 7 to 11 Challenge Level:

A magician took a suit of thirteen cards and held them in his hand face down. Every card he revealed had the same value as the one he had just finished spelling. How did this work?

### Painted Cube

##### Age 14 to 16 Challenge Level:

Imagine a large cube made from small red cubes being dropped into a pot of yellow paint. How many of the small cubes will have yellow paint on their faces?

### Air Nets

##### Age 7 to 18 Challenge Level:

Can you visualise whether these nets fold up into 3D shapes? Watch the videos each time to see if you were correct.

### Power Countdown

##### Age 14 to 16 Challenge Level:

In this twist on the well-known Countdown numbers game, use your knowledge of Powers and Roots to make a target.

### Sociable Cards

##### Age 11 to 14 Challenge Level:

Move your counters through this snake of cards and see how far you can go. Are you surprised by where you end up?

### Helicopters

##### Age 7 to 16 Challenge Level:

Design and test a paper helicopter. What is the best design?

### All Change

##### Age 5 to 7 Challenge Level:

There are three versions of this challenge. The idea is to change the colour of all the spots on the grid. Can you do it in fewer throws of the dice?

### Summing Geometric Progressions

##### Age 14 to 18 Challenge Level:

Watch the video to see how to sum the sequence. Can you adapt the method to sum other sequences?

### Seven Squares

##### Age 11 to 14 Challenge Level:

Watch these videos to see how Phoebe, Alice and Luke chose to draw 7 squares. How would they draw 100?

### Sorted

##### Age 14 to 18 Challenge Level:

How can you quickly sort a suit of cards in order from Ace to King?

### Perimeter Possibilities

##### Age 11 to 14 Challenge Level:

I'm thinking of a rectangle with an area of 24. What could its perimeter be?

### A Brief Introduction to Complex Numbers

##### Age 14 to 18 Challenge Level:

In this problem, we define complex numbers and invite you to explore what happens when you add and multiply them.

##### Age 11 to 18 Challenge Level:

Video for teachers of a talk given by Dan Meyer in Cambridge in March 2013.

### Strange Bank Account

##### Age 11 to 14 Challenge Level:

Imagine a very strange bank account where you are only allowed to do two things...

### Up, Down, Flying Around

##### Age 11 to 14 Challenge Level:

Play this game to learn about adding and subtracting positive and negative numbers

### Strike it Out for Two

##### Age 5 to 11 Challenge Level:

Strike it Out game for an adult and child. Can you stop your partner from being able to go?

### Dotty Six for Two

##### Age 5 to 11 Challenge Level:

Dotty Six game for an adult and child. Will you be the first to have three sixes in a straight line?

### Drawing Squares

##### Age 11 to 16

Take a look at the video showing squares drawn on dotty grids...

### Squares from Diagonals

##### Age 11 to 16

Take a look at the video showing squares and their diagonals...

### Drawing Rhombuses

##### Age 11 to 16

Take a look at the video showing rhombuses drawn on dotty grids...

### Rhombuses from Diagonals

##### Age 11 to 16

Take a look at the video showing rhombuses and their diagonals...

### Areas on a Grid

##### Age 11 to 16

Take a look at the video showing areas of different shapes on dotty grids...

### Sketching Graphs - Transformations

##### Age 16 to 18 Challenge Level:

If you can sketch y=f(x), there are several related functions you can also sketch...

### Subtraction Surprise

##### Age 7 to 14 Challenge Level:

Try out some calculations. Are you surprised by the results?

### Roll over the Dice

##### Age 7 to 11 Challenge Level:

Watch this video to see how to roll the dice. Now it's your turn! What do you notice about the dice numbers you have recorded?

### How Risky is My Diet?

##### Age 11 to 16 Challenge Level:

Newspapers said that eating a bacon sandwich every day raises the risk of bowel cancer by 20%. Should you be concerned?

### Statins and Risk

##### Age 14 to 16 Challenge Level:

"Statins cut the risks of heart attacks and strokes by 40%"
Should the Professor take statins? Can you help him decide?

### Probability in Court

##### Age 14 to 18 Challenge Level:

When you're on trial for murder, it can be crucial that the court understands probability...

### The ELISA Test

##### Age 14 to 18 Challenge Level:

In 1% of cases, an HIV test gives a positive result for someone who is HIV negative. How likely is it that someone who tests positive has HIV?

### Introductory Video

##### Age 11 to 16

An introductory video to the Probability and Evidence collection

### Vanishing Roots

##### Age 14 to 18

If $y=x^2-6x+c$, and we vary $c$, what happens to the roots when $c>9$?

### Maths for Parents 2017

Resources from Charlie's and Fran's 2017 Madingley course for parents.

### Pouring Problem

##### Age 7 to 11 Challenge Level:

What do you think is going to happen in this video clip? Are you surprised?

### Eightness of Eight

##### Age 5 to 7 Challenge Level:

What do you see as you watch this video? Can you create a similar video for the number 12?

### Tumbling Down

##### Age 7 to 11 Challenge Level:

Watch this animation. What do you see? Can you explain why this happens?

### Bundles of Cubes

##### Age 7 to 11 Challenge Level:

Watch this animation. What do you notice? What happens when you try more or fewer cubes in a bundle?

### Truth or Lie

##### Age 7 to 11 Challenge Level:

Take a look at the video of this trick. Can you perform it yourself? Why is this maths and not magic?

### Unexpected Ordering

##### Age 5 to 7 Challenge Level:

Watch the video of Fran re-ordering these number cards. What do you notice? Try it for yourself. What happens?

### Surprising Split

##### Age 7 to 11 Challenge Level:

Does this 'trick' for calculating multiples of 11 always work? Why or why not?

### Subtraction Slip

##### Age 5 to 7 Challenge Level:

Can you spot the mistake in this video? How would you work out the answer to this calculation?