Are these statements relating to odd and even numbers always true, sometimes true or never true?
Watch this video to see how to roll the dice. Now it's your turn! What do you notice about the dice numbers you have recorded?
Find a route from the outside to the inside of this square, stepping on as many tiles as possible.
Here are two kinds of spirals for you to explore. What do you notice?
This challenge asks you to imagine a snake coiling on itself.
In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?
An investigation that gives you the opportunity to make and justify predictions.
Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?
Can you dissect an equilateral triangle into 6 smaller ones? What number of smaller equilateral triangles is it NOT possible to dissect a larger equilateral triangle into?
Are these statements always true, sometimes true or never true?
Investigate the sum of the numbers on the top and bottom faces of a line of three dice. What do you notice?
Choose any 3 digits and make a 6 digit number by repeating the 3 digits in the same order (e.g. 594594). Explain why whatever digits you choose the number will always be divisible by 7, 11 and 13.
Only one side of a two-slice toaster is working. What is the quickest way to toast both sides of three slices of bread?
Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.
Make some loops out of regular hexagons. What rules can you discover?
Try adding together the dates of all the days in one week. Now multiply the first date by 7 and add 21. Can you explain what happens?
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
How many ways can you find to do up all four buttons on my coat? How about if I had five buttons? Six ...?
Can you explain how this card trick works?
Can you put the numbers 1-5 in the V shape so that both 'arms' have the same total?
Start with any number of counters in any number of piles. 2 players take it in turns to remove any number of counters from a single pile. The winner is the player to take the last counter.
Place the numbers from 1 to 9 in the squares below so that the difference between joined squares is odd. How many different ways can you do this?
This article for teachers describes several games, found on the site, all of which have a related structure that can be used to develop the skills of strategic planning.
Square numbers can be represented as the sum of consecutive odd numbers. What is the sum of 1 + 3 + ..... + 149 + 151 + 153?
We can show that (x + 1)² = x² + 2x + 1 by considering the area of an (x + 1) by (x + 1) square. Show in a similar way that (x + 2)² = x² + 4x + 4
The NRICH team are always looking for new ways to engage teachers and pupils in problem solving. Here we explain the thinking behind maths trails.
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
This challenge, written for the Young Mathematicians' Award, invites you to explore 'centred squares'.
Ben’s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?
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?
Delight your friends with this cunning trick! Can you explain how it works?
Find the sum and difference between a pair of two-digit numbers. Now find the sum and difference between the sum and difference! What happens?
This challenge focuses on finding the sum and difference of pairs of two-digit numbers.
Great Granddad is very proud of his telegram from the Queen congratulating him on his hundredth birthday and he has friends who are even older than he is... When was he born?
This task encourages you to investigate the number of edging pieces and panes in different sized windows.
Find the sum of all three-digit numbers each of whose digits is odd.
This challenge encourages you to explore dividing a three-digit number by a single-digit number.
Can you find all the ways to get 15 at the top of this triangle of numbers? Many opportunities to work in different ways.
This task follows on from Build it Up and takes the ideas into three dimensions!
Got It game for an adult and child. How can you play so that you know you will always win?
This activity involves rounding four-digit numbers to the nearest thousand.
What happens when you round these three-digit numbers to the nearest 100?
Can you explain the strategy for winning this game with any target?
The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?
In this game for two players, the idea is to take it in turns to choose 1, 3, 5 or 7. The winner is the first to make the total 37.
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
An article for teachers and pupils that encourages you to look at the mathematical properties of similar games.
When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...
Nim-7 game for an adult and child. Who will be the one to take the last counter?
Can you make dice stairs using the rules stated? How do you know you have all the possible stairs?