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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# Working with Numbers

### Shifting Times Tables

### What Numbers Can We Make?

### Take Three from Five

### What Numbers Can We Make Now?

### Charlie's Delightful Machine

### Got It

### An Introduction to Modular Arithmetic

Links to the University of Cambridge website
Links to the NRICH website Home page

Nurturing young mathematicians: teacher webinars

30 April (Primary), 1 May (Secondary)

30 April (Primary), 1 May (Secondary)

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The problems in this masterclass package are intended to be used in a computer room to introduce students to ideas in Number Theory.

Working on a selection of these activities builds on students' knowledge of multiples and allows them to develop and formalise their understanding of linear sequences, remainders and modular arithmetic.

Age 11 to 14

Challenge Level

Can you find a way to identify times tables after they have been shifted up or down?

Age 11 to 14

Challenge Level

Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

Age 11 to 16

Challenge Level

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?

Age 11 to 14

Challenge Level

Imagine we have four bags containing numbers from a sequence. What numbers can we make now?

Age 11 to 16

Challenge Level

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

Age 7 to 14

Challenge Level

A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.

Age 14 to 18

An introduction to the notation and uses of modular arithmetic