# Resource Title search

### U in a Pentagon

##### Age 11 to 14 Short Challenge Level:

Weekly Problem 18 - 2008
The diagram shows a regular pentagon. Can you work out the size of the marked angle?

### UKMT 2007

Content for UKMT 2007

### UKMT 2008

Resources to support UKMT 2008 Teacher Meeting presentations

### UKMT 2012 Teacher Meetings

Resources to accompany NRICH team presentations at UKMT 2012 Teacher Meetings.

### UKMT 2013 Teacher Meetings

Resources to accompany NRICH team presentations at UKMT 2013 Teacher Meetings.

### UKMT 2014 Teacher Meetings

Resources to accompany NRICH team presentations at UKMT 2014 Teacher Meetings.

### UKMT 2015 Teacher Meetings

##### Age 11 to 18

Resources to accompany NRICH team presentations at UKMT 2015 Teacher Meetings.

### UKMT 2016 Teacher Meetings

Resources to accompany NRICH team presentations at UKMT 2016 Teacher Meetings.

### Uncanny Triangles

##### Age 7 to 11 Challenge Level:

Can you help the children find the two triangles which have the lengths of two sides numerically equal to their areas?

### Under the Ribbon

##### Age 14 to 16 Challenge Level:

A ribbon is nailed down with a small amount of slack. What is the largest cube that can pass under the ribbon ?

### Underground Mathematics

##### Age 16 to 18 Challenge Level:

Check out the new Underground Maths website

### Underground Mathematics

##### Age 16 to 18 Challenge Level:

Check out the new Underground Maths website

### Understanding Information

Deepen your understanding of different types of information with these challenges.

### Understanding Information

##### Age 7 to 11

Deepen your understanding of different types of information with these upper primary challenges.

### Understanding Information

##### Age 5 to 7

These lower primary challenges focus on different types of information.

### Understanding Inverse Relationships

##### Age 11 to 18 Challenge Level:

The problems in this feature encourage students to consider inverses and working backwards to solve problems.

### Unequal Averages

##### Age 11 to 14 Challenge Level:

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

### Unexpected Ordering

##### Age 5 to 7 Challenge Level:

Watch the video of Fran re-ordering these number cards. What do you notice? Try it for yourself. What happens?

### Uniform Sum?

##### Age 16 to 18 Challenge Level:

Is the sum or difference of two uniform random variables uniform?

### Uniform Units

##### Age 14 to 16 Challenge Level:

Can you choose your units so that a cube has the same numerical value for it volume, surface area and total edge length?

### Uniformly Unstable

##### Age 16 to 18 Challenge Level:

Invent shapes with different numbers of stable and unstable equilibrium points

### Unit Differences

##### Age 5 to 7 Challenge Level:

This challenge is about finding the difference between numbers which have the same tens digit.

### Unit Fractions

##### Age 11 to 14 Challenge Level:

Consider the equation 1/a + 1/b + 1/c = 1 where a, b and c are natural numbers and 0 < a < b < c. Prove that there is only one set of values which satisfy this equation.

### Unit Interval

##### Age 16 to 18 Short Challenge Level:

Can you prove our inequality holds for all values of x and y between 0 and 1?

### Unit Interval

##### Age 14 to 18 Challenge Level:

Take any two numbers between 0 and 1. Prove that the sum of the numbers is always less than one plus their product?

### Units

The Units collection of STEM resources

### Universal Time, Mass, Length

##### Age 16 to 18 Short Challenge Level:

Can you work out the natural time scale for the universe?

### Unlocking the Case

##### Age 7 to 11 Challenge Level:

A case is found with a combination lock. There is one clue about the number needed to open the case. Can you find the number and open the case?

### Unusual Long Division - Square Roots Before Calculators

##### Age 14 to 16 Challenge Level:

However did we manage before calculators? Is there an efficient way to do a square root if you have to do the work yourself?

### Unusual Polygon

##### Age 14 to 16 Short Challenge Level:

What is the perimeter of this unusually shaped polygon...

##### Age 14 to 16 Short Challenge Level:

This quadrilateral has an unusual shape. Are you able to find its area?

### Up a Semitone?

##### Age 16 to 18 Challenge Level:

Fifth challenge cipher

### Up and Across

##### Age 11 to 14 Challenge Level:

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

### Up and Down

##### Age 5 to 7 Challenge Level:

Sam got into an elevator. He went down five floors, up six floors, down seven floors, then got out on the second floor. On what floor did he get on?

### Up and Down Donkey

##### Age 5 to 11 Challenge Level:

A number card game for 2-6 players.

### Up and Down Staircases

##### Age 7 to 11 Challenge Level:

One block is needed to make an up-and-down staircase, with one step up and one step down. How many blocks would be needed to build an up-and-down staircase with 5 steps up and 5 steps down?

### Up or Down?

##### Age 11 to 14 Challenge Level:

How high can you reach?

### Up, Down, Flying Around

##### Age 11 to 14 Challenge Level:

Play this game to learn about adding and subtracting positive and negative numbers

### Upper Primary Flash Interactives

##### Age 7 to 11

Flash interactives for upper primary.

### Upper Primary Games Using Counters

##### Age 7 to 11

Here are some games which use counters.

##### Age 7 to 11

Although almost any NRICH activity could be tackled in a group, these upper primary activities have been created specifically with group work in mind.

### Upper Primary Non-flash Interactives

##### Age 7 to 11

Non-Flash interactives for upper primary.

### Upper Primary Working Systematically KS2

##### Age 7 to 11 Challenge Level:

Activities for upper primary children which focus on working systematically.

### Upper Secondary - Complete Article Index

##### Age 14 to 18

The archive of our upper secondary student articles.

### Upper Secondary Latest

Latest content for Upper Secondary

### Upsetting Pitagoras

##### Age 14 to 18 Challenge Level:

Find the smallest integer solution to the equation 1/x^2 + 1/y^2 = 1/z^2

### Useful Graphing Tools

A collection of useful graphing resources to support work on NRICH problems.

### Using Books: Maisy Goes Camping

##### Age 3 to 5

Read the book 'Maisy Goes Camping' by Lucy Cousins. Act out the story with some toys - is there room for one more in the tent? How many characters are in the tent now?

### Using Books: the Doorbell Rang

##### Age 3 to 5

Read the book 'The Doorbell Rang' by Pat Hutchins. Have a go at sharing out some cookies like the characters in the story!