# Resource Title search

### 2 Rings

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

The red ring is inside the blue ring in this picture. Can you rearrange the rings in different ways? Perhaps you can overlap them or put one outside another?

### 2,4,6,8

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

Using the cards 2, 4, 6, 8, +, - and =, what number statements can you make?

### 2-digit Square

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

A 2-Digit number is squared. When this 2-digit number is reversed and squared, the difference between the squares is also a square. What is the 2-digit number?

### 2001 Spatial Oddity

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

With one cut a piece of card 16 cm by 9 cm can be made into two pieces which can be rearranged to form a square 12 cm by 12 cm. Explain how this can be done.

### 2009 Challenge

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

We asked what was the most interesting fact that you can find out about the number 2009. See the solutions that were submitted.

### 2010: A Year of Investigations

##### Age 5 to 14

This article for teachers suggests ideas for activities built around 10 and 2010.

### 2011 Digits

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

Weekly Problem 10 - 2014
What is the sum of the first $2011$ digits when $20 \div 11$ is written as a decimal?

### 2014 Even Numbers

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

What is the difference between the sum of the first 2014 odd numbers and the sum of the first 2014 even numbers?

### 2017 ATM and MA Conferences - Secondary

Resources used by the NRICH Secondary team in their sessions at the 2017 ATM Easter and MA Stirling conferences.

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

Twenty-four tasks for the run-up to Christmas.

##### Age 11 to 16

Count down to Christmas with our Advent Calendar

### 2018 BCME Secondary Workshop

##### Age 11 to 16

Resources used by Alison and Charlie in their workshop at BCME 2018.

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

Twenty-four tasks for the run-up to Christmas.

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

Twenty four tasks to count down to Christmas.

### 24 Hour Conundrum

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

It is 225 minutes until midnight. What time is it on a 24-hour digital clock?

### 28 and It's Upward and Onward

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

Can you find ways of joining cubes together so that 28 faces are visible?

### 2d and 3d

##### Age 11 to 16

The 2d and 3d collection of STEM resources

### 2D-3D

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

Two circles of equal size intersect and the centre of each circle is on the circumference of the other. What is the area of the intersection? Now imagine that the diagram represents two spheres of. . . .

### 2nd STEM TI Day 2011/12

##### Age 11 to 18

Resources from the second STEM TI day, March 2012.

### 2nd Stemnrich T I Day 17 April 2013

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

A holding page for the resources and links from the second stemNRICH TI day for 2012-13.

### 2^n -n Numbers

##### Age 16 to 18

Yatir from Israel wrote this article on numbers that can be written as $2^n-n$ where n is a positive integer.