
Pumpkin patch

Seega

Alquerque

Introducing NRICH TWILGO

Like a circle in a spiral

Fruity totals
In this interactivity each fruit has a hidden value. Can you deduce what each one is worth?

Air nets

Clocking off

Prime magic


Instant insanity
Given the nets of 4 cubes with the faces coloured in 4 colours, build a tower so that on each vertical wall no colour is repeated, that is all 4 colours appear.

Funny factorisation

What's it worth?
There are lots of different methods to find out what the shapes are worth - how many can you find?

LOGO challenge - circles as animals
See if you can anticipate successive 'generations' of the two animals shown here.


Charlie's delightful machine
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?

Charting success

Nine colours



LOGO challenge - triangles-squares-stars
Can you recreate these designs? What are the basic units? What movement is required between each unit? Some elegant use of procedures will help - variables not essential.

Charting more success

Hamiltonian cube
Find the length along the shortest path passing through certain points on the cube.


Take three from five
Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?

Searching for mean(ing)

Sliding puzzle


Ding dong bell

Triangle in a trapezium
Can you find and prove the relationship between the area of a trapezium and the area of a triangle constructed within it?

What is the question?

Shaping the universe I - planet Earth
This article explores ths history of theories about the shape of our planet. It is the first in a series of articles looking at the significance of geometric shapes in the history of astronomy.

Marbles in a box
How many winning lines can you make in a three-dimensional version of noughts and crosses?

Shaping the universe II - the solar system
The second in a series of articles on visualising and modelling shapes in the history of astronomy.

The bridges of Konigsberg
Investigate how networks can be used to solve a problem for the 18th Century inhabitants of Konigsberg.

Yih or Luk tsut k'i or Three Men's Morris
Some puzzles requiring no knowledge of knot theory, just a careful inspection of the patterns. A glimpse of the classification of knots and a little about prime knots, crossing numbers and knot arithmetic.


Shaping the universe III - to infinity and beyond
The third installment in our series on the shape of astronomical systems, this article explores galaxies and the universe beyond our solar system.

Triangles in the middle

Sprouts

Back fitter
10 graphs of experimental data are given. Can you use a spreadsheet to find algebraic graphs which match them closely, and thus discover the formulae most likely to govern the underlying processes?


All tied up

Cubic covering


Quadratic patterns
Surprising numerical patterns can be explained using algebra and diagrams...



Surprising transformations
I took the graph y=4x+7 and performed four transformations. Can you find the order in which I could have carried out the transformations?


Just rolling round

Out of the window


Around and back


Pythagoras perimeters

Jam
To avoid losing think of another very well known game where the patterns of play are similar.

Coke machine


Triangle midpoints
You are only given the three midpoints of the sides of a triangle. How can you construct the original triangle?

Nicely similar
If the hypotenuse (base) length is 100cm and if an extra line splits the base into 36cm and 64cm parts, what were the side lengths for the original right-angled triangle?

Packing 3D shapes
What 3D shapes occur in nature. How efficiently can you pack these shapes together?

Wari

Vector walk

Just opposite

Bus stop


Doesn't add up
In this problem we are faced with an apparently easy area problem, but it has gone horribly wrong! What happened?

Dating made easier



Terminology


Inside out
There are 27 small cubes in a 3 x 3 x 3 cube, 54 faces being visible at any one time. Is it possible to reorganise these cubes so that by dipping the large cube into a pot of paint three times you can colour every face of all of the smaller cubes?

Facial sums

Fermat's poser

Steel cables

Gnomon dimensions

Partly circles
What is the same and what is different about these circle questions? What connections can you make?

Summing squares

Sliced


A problem of time

Rectangle rearrangement

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


Pick's theorem

Circuit training


Hypotenuse lattice points

Iff

A question of scale


Corridors

Something in common

Packing boxes

Star gazing


Tetra square
