Calendar Capers
Stage: 3 Challenge Level: 
Choose any three by three square of dates on a calendar page...
Have You Got It?
Stage: 3 Challenge Level:
Can you explain the strategy for winning this game with any target?
Summing Consecutive Numbers
Stage: 3 Challenge Level:
Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?
What's Possible?
Stage: 4 Challenge Level:
Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?
Marbles in a Box
Stage: 3 Challenge Level:
How many winning lines can you make in a three-dimensional version of noughts and crosses?
Attractive Tablecloths
Stage: 4 Challenge Level:
Charlie likes tablecloths that use as many colours as possible, but insists that his tablecloths have some symmetry. Can you work out how many colours he needs for different tablecloth designs?
1 Step 2 Step
Stage: 3 Challenge Level:
Liam's house has a staircase with 12 steps. He can go down the steps one at a time or two at time. In how many different ways can Liam go down the 12 steps?
Pick's Theorem
Stage: 3 Challenge Level:
Polygons drawn on square dotty paper have dots on their perimeter (p) and often internal (i) ones as well. Find a relationship between p, i and the area of the polygons.
Pair Products
Stage: 4 Challenge Level:
Choose four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?
Number Pyramids
Stage: 3 Challenge Level:
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
Tilted Squares
Stage: 3 Challenge Level:
It's easy to work out the areas of most squares that we meet, but what if they were tilted?
Painted Cube
Stage: 3 Challenge Level:
Imagine a large cube made from small red cubes being dropped into a pot of yellow paint. How many of the small cubes will have yellow paint on their faces?
Arithmagons
Stage: 4 Challenge Level:
Can you find the values at the vertices when you know the values on the edges?
Odds and Evens
Stage: 3 Challenge Level:
Is this a fair game? How many ways are there of creating a fair game by adding odd and even numbers?
Route to Infinity
Stage: 3 Challenge Level:
Can you describe this route to infinity? Where will the arrows take you next?
Interactive Spinners
Stage: 3 Challenge Level:
This interactivity invites you to make conjectures and explore probabilities of outcomes related to two independent events.
Keep it Simple
Stage: 3 Challenge Level:
Can all unit fractions be written as the sum of two unit fractions?
Cyclic Quadrilaterals
Stage: 3 Challenge Level:
What can you say about the angles on opposite vertices of any cyclic quadrilateral? Working on the building blocks will give you insights that may help you to explain what is special about them.
Shifting Times Tables
Stage: 3 Challenge Level:
Can you find a way to identify times tables after they have been shifted up?
Charlie's Delightful Machine
Stage: 3 and 4 Challenge Level:
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
What Numbers Can We Make?
Stage: 3 Challenge Level:
Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?
Vector Journeys
Stage: 4 Challenge Level:
Charlie likes to go for walks around a square park, while Alison likes to cut across diagonally. Can you find relationships between the vectors they walk along?
Magic Letters
Stage: 3 Challenge Level:
Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?
Seven Squares
Stage: 3 Challenge Level:
Watch these videos to see how Phoebe, Alice and Luke chose to draw 7 squares. How would they draw 100?
Exploring and Noticing Structure - Short Problems
Stage: 3 and 4
A collection of short Stage 3 and 4 problems on Exploring and Noticing Structure.
NRICH is part of the family of activities in the Millennium Mathematics Project.