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History of Measurement

This article tells you all about some early ways of measuring as well as methods of measuring tall objects we can still use today. You can even have a go at some yourself!

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Can You Find a Perfect Number?

Can you find any perfect numbers? Read this article to find out more...

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Fibonacci's Three Wishes 1

First or two articles about Fibonacci, written for students.

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Fibonacci's Three Wishes 2

Second of two articles about Fibonacci, written for students.

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Leonardo of Pisa and the Golden Rectangle

Leonardo who?! Well, Leonardo is better known as Fibonacci and this article will tell you some of fascinating things about his famous sequence.

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A-maze-ing

Did you know that ancient traditional mazes often tell a story? Remembering the story helps you to draw the maze.

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An Introduction to Magic Squares

Find out about Magic Squares in this article written for students. Why are they magic?!

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Going Places with Mathematicians

This article looks at the importance in mathematics of representing places and spaces mathematics. Many famous mathematicians have spent time working on problems that involve moving and mapping things.

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Clever Carl

What would you do if your teacher asked you add all the numbers from 1 to 100? Find out how Carl Gauss responded when he was asked to do just that.

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All Is Number

Read all about Pythagoras' mathematical discoveries in this article written for students.

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Paradoxes

A paradox is a statement that seems to be both untrue and true at the same time. This article looks at a few examples and challenges you to investigate them for yourself.

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Palindromes

Find out about palindromic numbers by reading this article.

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The Moving Planets

Mathematics has always been a powerful tool for studying, measuring and calculating the movements of the planets, and this article gives several examples.

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The Königsberg Bridge Problem

This article for pupils describes the famous Konigsberg Bridge problem.

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Arclets Explained

This article gives an wonderful insight into students working on the Arclets problem that first appeared in the Sept 2002 edition of the NRICH website.

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Eclipses of the Sun

Mathematics has allowed us now to measure lots of things about eclipses and so calculate exactly when they will happen, where they can be seen from, and what they will look like.

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Friezes

Some local pupils lost a geometric opportunity recently as they surveyed the cars in the car park. Did you know that car tyres, and the wheels that they on, are a rich source of geometry?

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On What Day Did it Happen?

Read this article to find out the mathematical method for working out what day of the week each particular date fell on back as far as 1700.

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The Secret World of Codes and Code Breaking

When you think of spies and secret agents, you probably wouldn’t think of mathematics. Some of the most famous code breakers in history have been mathematicians.

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Pi, a Very Special Number

Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.

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History of Morse

This short article gives an outline of the origins of Morse code and its inventor and how the frequency of letters is reflected in the code they were given.

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More on Mazes

There is a long tradition of creating mazes throughout history and across the world. This article gives details of mazes you can visit and those that you can tackle on paper.

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Calendars

Calendars were one of the earliest calculating devices developed by civilizations. Find out about the Mayan calendar in this article.

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I've Submitted a Solution - What Next?

In this article, the NRICH team describe the process of selecting solutions for publication on the site.

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Got It! Article

This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.

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Pythagoras

Pythagoras of Samos was a Greek philosopher who lived from about 580 BC to about 500 BC. Find out about the important developments he made in mathematics, astronomy, and the theory of music.

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Mathematical Symbols

A brief article written for pupils about mathematical symbols.

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Liethagoras' Theorem

Liethagoras, Pythagoras' cousin (!), was jealous of Pythagoras and came up with his own theorem. Read this article to find out why other mathematicians laughed at him.

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The Cyclic Quadrilateral

This gives a short summary of the properties and theorems of cyclic quadrilaterals and links to some practical examples to be found elsewhere on the site.

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Whirling Fibonacci Squares

Draw whirling squares and see how Fibonacci sequences and golden rectangles are connected.

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Muggles, Logo and Gradients

Logo helps us to understand gradients of lines and why Muggles Magic is not magic but mathematics. See the problem Muggles magic.

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What Are Numbers?

Ranging from kindergarten mathematics to the fringe of research this informal article paints the big picture of number in a non technical way suitable for primary teachers and older students.

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Ding Dong Bell

The reader is invited to investigate changes (or permutations) in the ringing of church bells, illustrated by braid diagrams showing the order in which the bells are rung.

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Latin Squares

A Latin square of order n is an array of n symbols in which each symbol occurs exactly once in each row and exactly once in each column.

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The Frieze Tree

Patterns that repeat in a line are strangely interesting. How many types are there and how do you tell one type from another?

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Paint Rollers for Frieze Patterns.

Proofs that there are only seven frieze patterns involve complicated group theory. The symmetries of a cylinder provide an easier approach.

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Logic, Truth Tables and Switching Circuits Challenge

Learn about the link between logical arguments and electronic circuits. Investigate the logical connectives by making and testing your own circuits and fill in the blanks in truth tables to record your findings.

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Truth Tables and Electronic Circuits

Investigate circuits and record your findings in this simple introduction to truth tables and logic.

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Learn about Number Bases

We are used to writing numbers in base ten, using 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Eg. 75 means 7 tens and five units. This article explains how numbers can be written in any number base.

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Bands and Bridges: Bringing Topology Back

Lyndon Baker describes how the Mobius strip and Euler's law can introduce pupils to the idea of topology.

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Roasting Old Chestnuts

Mainly for teachers. A discussion and examples of some of the school mathematics of yesteryear.

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More Old Chestnuts

Mainly for teachers. More school mathematics of yesteryear.

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Tangles

A personal investigation of Conway's Rational Tangles. What were the interesting questions that needed to be asked, and where did they lead?

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Divisibility Tests

This article takes the reader through divisibility tests and how they work. An article to read with pencil and paper to hand.

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Generic Examples: Seeing Through the Particular to the General

Can one example help us to perceive the generality?

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Pythagorean Triples I

The first of two articles on Pythagorean Triples which asks how many right angled triangles can you find with the lengths of each side exactly a whole number measurement. Try it!

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Pythagorean Triples II

This is the second article on right-angled triangles whose edge lengths are whole numbers.

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Geometry and Gravity 1

This article (the first of two) contains ideas for investigations. Space-time, the curvature of space and topology are introduced with some fascinating problems to explore.

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Geometry and Gravity 2

This is the second of two articles and discusses problems relating to the curvature of space, shortest distances on surfaces, triangulations of surfaces and representation by graphs.

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Zooming in on the Squares

Start with a large square, join the midpoints of its sides, you'll see four right angled triangles. Remove these triangles, a second square is left. Repeat the operation. What happens?

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Frieze Patterns in Cast Iron

A gallery of beautiful photos of cast ironwork friezes in Australia with a mathematical discussion of the classification of frieze patterns.

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An Investigation Based on Score

Class 2YP from Madras College was inspired by the problem in NRICH to work out in how many ways the number 1999 could be expressed as the sum of 3 odd numbers, and this is their solution.

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Ways of Summing Odd Numbers

Sanjay Joshi, age 17, The Perse Boys School, Cambridge followed up the Madrass College class 2YP article with more thoughts on the problem of the number of ways of expressing an integer as the sum of odd numbers.

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Impossible Sandwiches

In this 7-sandwich: 7 1 3 1 6 4 3 5 7 2 4 6 2 5 there are 7 numbers between the 7s, 6 between the 6s etc. The article shows which values of n can make n-sandwiches and which cannot.

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Magic Sums and Products

How to build your own magic squares.

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The Codabar Check

This article explains how credit card numbers are defined and the check digit serves to verify their accuracy.

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Magic Squares for Special Occasions

This article explains how to make your own magic square to mark a special occasion with the special date of your choice on the top line.

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Con Tricks

Here are some examples of 'cons', and see if you can figure out where the trick is.

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Squareo'scope Determines the Kind of Triangle

A description of some experiments in which you can make discoveries about triangles.

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Volume of a Pyramid and a Cone

These formulae are often quoted, but rarely proved. In this article, we derive the formulae for the volumes of a square-based pyramid and a cone, using relatively simple mathematical concepts.

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What Is the Circle Scribe Disk Compass?

Introducing a geometrical instrument with 3 basic capabilities.

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A Story about Absolutely Nothing

This article for the young and old talks about the origins of our number system and the important role zero has to play in it.

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Tournament Scheduling

Scheduling games is a little more challenging than one might desire. Here are some tournament formats that sport schedulers use.

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Dancing with Maths

An article for students and teachers on symmetry and square dancing. What do the symmetries of the square have to do with a dos-e-dos or a swing? Find out more?

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Paper Folding - Models of the Platonic Solids

A description of how to make the five Platonic solids out of paper.

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Sprouts Explained

This article invites you to get familiar with a strategic game called "sprouts". The game is simple enough for younger children to understand, and has also provided experienced mathematicians with significant food for thought.

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Mathematical Patchwork

Jenny Murray describes the mathematical processes behind making patchwork in this article for students.

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On Time?

This article explains how Greenwich Mean Time was established and in fact, why Greenwich in London was chosen as the standard.

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History of Fractions

Who first used fractions? Were they always written in the same way? How did fractions reach us here? These are the sorts of questions which this article will answer for you.

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Maurits Cornelius Escher

Have you ever noticed how mathematical ideas are often used in patterns that we see all around us? This article describes the life of Escher who was a passionate believer that maths and art can be intertwined.

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Eureka!

Read this article to find out about the discoveries and inventions of Archimedes.

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Coordinates and Descartes

Have you ever wondered how maps are made? Or perhaps who first thought of the idea of designing maps? We're here to answer these questions for you.

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History of Money

If you would like a new CD you would probably go into a shop and buy one using coins or notes. (You might need to do a bit of saving first!) However, this way of paying for the things you want did not always exist. Find out more ...

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Logic

What does logic mean to us and is that different to mathematical logic? We will explore these questions in this article.

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Adding with the Abacus

Nowadays the calculator is very familiar to many of us. What did people do to save time working out more difficult problems before the calculator existed?

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The Dangerous Ratio

This article for pupils and teachers looks at a number that even the great mathematician, Pythagoras, found terrifying.

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All about Infinity

Infinity is not a number, and trying to treat it as one tends to be a pretty bad idea. At best you're likely to come away with a headache, at worse the firm belief that 1 = 0. This article discusses the different types of infinity.

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Grouping Transformations

An introduction to groups using transformations, following on from the October 2006 Stage 3 problems.

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Corresponding Sudokus

This second Sudoku article discusses "Corresponding Sudokus" which are pairs of Sudokus with terms that can be matched using a substitution rule.

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The Naked Pair in Sudoku

A particular technique for solving Sudoku puzzles, known as "naked pair", is explained in this easy-to-read article.

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Sums of Powers - A Festive Story

A story for students about adding powers of integers - with a festive twist.

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Card Shuffle

This article for students and teachers tries to think about how long would it take someone to create every possible shuffle of a pack of cards, with surprising results.

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Getting Started with Solving Rich Tasks

Need some help getting started with solving and thinking about rich tasks? Read on for some friendly advice.

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The Random World

Think that a coin toss is 50-50 heads or tails? Read on to appreciate the ever-changing and random nature of the world in which we live.

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Weekly Challenges Are Here!

Weekly challenges are here for NRICH! To celebrate this event, we've collected a set of 20 essential problems for you to try.

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Mathematical Ways to Spend Your Summer

Here we look back at the year with NRICH and suggest mathematical summer holiday activities for students, parents and teachers.

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Understanding Hypotheses

This article explores the process of making and testing hypotheses.

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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.

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Circles, Circles Everywhere

This article for pupils gives some examples of how circles have featured in people's lives for centuries.

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Negative Numbers

A brief history of negative numbers throughout the ages

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Women in Maths

Most stories about the history of maths seem to be about men. Here are some famous women who contributed to the development of modern maths and prepared the way for generations of female mathematicians.

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Maths in the Victorian Classroom

What was it like to learn maths at school in the Victorian period? We visited the British Schools Museum in Hitchin to find out.

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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.

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Shaping the Universe II - the Solar System

The second in a series of articles on visualising and modelling shapes in the history of astronomy.

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Plaiting and Braiding

This article for students gives some instructions about how to make some different braids.

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Celtic Knotwork Patterns

This article for pupils gives an introduction to Celtic knotwork patterns and a feel for how you can draw them.

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Drawing Doodles and Naming Knots

This article for students introduces the idea of naming knots using numbers. You'll need some paper and something to write with handy!

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Geometry: A History from Practice to Abstraction

This article gives a brief history of the development of Geometry.

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The Development of Algebra - 1

This is the first of a two part series of articles on the history of Algebra from about 2000 BCE to about 1000 CE.

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The Development of Algebra - 2

This is the second article in a two part series on the history of Algebra from about 2000 BCE to about 1000 CE.

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The History of Trigonometry- Part 1

The first of three articles on the History of Trigonometry. This takes us from the Egyptians to early work on trigonometry in China.

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History of Trigonometry - Part 2

The second of three articles on the History of Trigonometry.

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Ancient Astronomical Terms

Some explanations of basic terms and some phenomena discovered by ancient astronomers

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History of Trigonometry - Part 3

The third of three articles on the History of Trigonometry.

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A Brief History of Time Measurement

Noticing the regular movement of the Sun and the stars has led to a desire to measure time. This article for teachers and learners looks at the history of man's need to measure things.

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From A Random World to a Rational Universe

In the time before the mathematical idea of randomness was discovered, people thought that everything that happened was part of the will of supernatural beings. So have things changed?

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The Four Colour Theorem

The Four Colour Conjecture was first stated just over 150 years ago, and finally proved conclusively in 1976. It is an outstanding example of how old ideas can be combined with new discoveries. prove a mathematical theorem.

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Where Art and Maths Combine

In this article, Rachel Melrose describes what happens when she mixed mathematics with art.

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An Introduction to Tree Diagrams

This article explains how tree diagrams are constructed and helps you to understand how they can be used to calculate probabilities.

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Why Do People Find Probability Unintuitive and Difficult?

Uncertain about the likelihood of unexpected events? You are not alone!

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Programming: Moiré Patterns

We need computer programmers! Logo is a great entry-level programming language - and you can create stunning graphics while you learn.

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3D Drawing

The design technology curriculum requires students to be able to represent 3-dimensional objects on paper. This article introduces some of the mathematical ideas which underlie such methods.

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On the Importance of Pedantry

A introduction to how patterns can be deceiving, and what is and is not a proof.

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Making Estimates

When making estimates, it is easy to be quite wrong, but it only takes a little thought to be almost right. In this article, we explore a few techniques and methods which will make our estimations better.

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Keeping it Safe and Quiet

Simon Singh describes PKC, its origins, and why the science of code making and breaking is such a secret occupation.

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What Did Turing Do for Us?

Dr James Grime takes an Enigma machine in to schools. Here he describes how the code-breaking work of Turing and his contemporaries helped to win the war.

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Decathlon: the Art of Scoring Points

How do decisions about scoring affect who wins a combined event such as the decathlon?

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Models in Mind

This article looks at how models support mathematical thinking about numbers and the number system

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Go Forth and Generalise

Spotting patterns can be an important first step - explaining why it is appropriate to generalise is the next step, and often the most interesting and important.


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