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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### For younger learners

### Advanced mathematics

# Special Numbers

### M, M and M

### Keep it Simple

### Egyptian Fractions

### Peaches Today, Peaches Tomorrow...

### Twisting and Turning

### Unequal Averages

### Power Mad!

### The Greedy Algorithm

### Wipeout

### Searching for Mean(ing)

### Big Powers

### Generating Triples

### Hollow Squares

### Plus Minus

### Fair Shares?

### What's Possible?

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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In some senses, all numbers are special, though some are perhaps given more attention than others...

The Special Numbers pathway on wild.maths.org invites**students** to take a closer look at some familiar categories of number and operations, and perhaps discover that there's a lot more to averages, fractions and square numbers than they might
have initially thought.

The collection of related NRICH tasks below are ideal for teachers who want to promote creativity in the classroom. They are designed for classroom use, with accompanying Teachers' Notes and Resources.

The Special Numbers pathway on wild.maths.org invites

The collection of related NRICH tasks below are ideal for teachers who want to promote creativity in the classroom. They are designed for classroom use, with accompanying Teachers' Notes and Resources.

Age 11 to 14

Challenge Level

If you are given the mean, median and mode of five positive whole numbers, can you find the numbers?

Age 11 to 14

Challenge Level

Can all unit fractions be written as the sum of two unit fractions?

Age 11 to 14

Challenge Level

The Egyptians expressed all fractions as the sum of different unit fractions. Here is a chance to explore how they could have written different fractions.

Age 11 to 14

Challenge Level

A monkey with peaches, keeps a fraction of them each day, gives the rest away, and then eats one. How long can his peaches last?

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.

Age 11 to 14

Challenge Level

Play around with sets of five numbers and see what you can discover about different types of average...

Age 11 to 14

Challenge Level

Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.

Age 11 to 14

Challenge Level

The Egyptians expressed all fractions as the sum of different unit fractions. The Greedy Algorithm might provide us with an efficient way of doing this.

Age 11 to 16

Challenge Level

Can you do a little mathematical detective work to figure out which number has been wiped out?

Age 11 to 16

Challenge Level

If you have a large supply of 3kg and 8kg weights, how many of each would you need for the average (mean) of the weights to be 6kg?

Age 11 to 16

Challenge Level

Three people chose this as a favourite problem. It is the sort of problem that needs thinking time - but once the connection is made it gives access to many similar ideas.

Age 14 to 16

Challenge Level

Sets of integers like 3, 4, 5 are called Pythagorean Triples, because they could be the lengths of the sides of a right-angled triangle. Can you find any more?

Age 14 to 16

Challenge Level

Which armies can be arranged in hollow square fighting formations?

Age 14 to 16

Challenge Level

Can you explain the surprising results Jo found when she calculated the difference between square numbers?

Age 14 to 16

Challenge Level

A mother wants to share a sum of money by giving each of her children in turn a lump sum plus a fraction of the remainder. How can she do this in order to share the money out equally?

Age 14 to 16

Challenge Level

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?