### Picturing Triangular Numbers

### How far does it move?

Experiment with the interactivity of "rolling" regular polygons, and explore how the different positions of the dot affects the distance it travels at each stage.

### Semi-regular Tessellations

Semi-regular tessellations combine two or more different regular polygons to fill the plane. Can you find all the semi-regular tessellations?

### Round and round and round

### Reflecting Lines

### Translating Lines

### Diminishing Returns

### At least one...

Imagine flipping a coin a number of times. Can you work out the probability you will get a head on at least one of the flips?

### Growing Surprises

### Days and Dates

### Think of Two Numbers

### Square coordinates

A tilted square is a square with no horizontal sides. Can you devise a general instruction for the construction of a square when you are given just one of its sides?

### Speeding up, slowing down

Experiment with the interactivity of "rolling" regular polygons, and explore how the different positions of the dot affects its speed at each stage.

### Triangle Numbers

### Tower of Hanoi

### Opposite vertices

Can you recreate squares and rhombuses if you are only given a side or a diagonal?

### Fill Me Up

Can you sketch graphs to show how the height of water changes in different containers as they are filled?

### Quadrilaterals in a Square

### Impossibilities

Just because a problem is impossible doesn't mean it's difficult...

### The Farmers' Field Boundary

### Counting Factors

### Alison's quilt

### Legs Eleven

### Funny Factorisation

### Marbles in a box

### Cuboids

### Efficient cutting

### Up and across

Experiment with the interactivity of "rolling" regular polygons, and explore how the different positions of the dot affects its vertical and horizontal movement at each stage.