This task encourages you to investigate the number of edging pieces and panes in different sized windows.

Is it possible to place 2 counters on the 3 by 3 grid so that there is an even number of counters in every row and every column? How about if you have 3 counters or 4 counters or....?

Can you work out how to balance this equaliser? You can put more than one weight on a hook.

Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.

Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.

A game for 2 people. Take turns placing a counter on the star. You win when you have completed a line of 3 in your colour.

In this maze of hexagons, you start in the centre at 0. The next hexagon must be a multiple of 2 and the next a multiple of 5. What are the possible paths you could take?

Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?

In this problem it is not the squares that jump, you do the jumping! The idea is to go round the track in as few jumps as possible.

Solve this Sudoku puzzle whose clues are in the form of sums of the numbers which should appear in diagonal opposite cells.

Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.

I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?

Add or subtract the two numbers on the spinners and try to complete a row of three. Are there some numbers that are good to aim for?

Can you arrange the digits 1, 1, 2, 2, 3 and 3 to make a Number Sandwich?

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Place the numbers 1 to 8 in the circles so that no consecutive numbers are joined by a line.

This challenge extends the Plants investigation so now four or more children are involved.

This challenge involves calculating the number of candles needed on birthday cakes. It is an opportunity to explore numbers and discover new things.

Frances and Rishi were given a bag of lollies. They shared them out evenly and had one left over. How many lollies could there have been in the bag?

A challenging activity focusing on finding all possible ways of stacking rods.

Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?

There is a long tradition of creating mazes throughout history and across the world. This article gives details of mazes you can visit and those that you can tackle on paper.

This cube has ink on each face which leaves marks on paper as it is rolled. Can you work out what is on each face and the route it has taken?

How many trains can you make which are the same length as Matt's, using rods that are identical?

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.

Make your own double-sided magic square. But can you complete both sides once you've made the pieces?

Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?

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.

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?

Can you find all the different ways of lining up these Cuisenaire rods?

Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.

You have 4 red and 5 blue counters. How many ways can they be placed on a 3 by 3 grid so that all the rows columns and diagonals have an even number of red counters?

Can you order the digits from 1-3 to make a number which is divisible by 3 so when the last digit is removed it becomes a 2-figure number divisible by 2, and so on?

Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?

Exactly 195 digits have been used to number the pages in a book. How many pages does the book have?

Try out the lottery that is played in a far-away land. What is the chance of winning?

Use the information to describe these marbles. What colours must be on marbles that sparkle when rolling but are dark inside?

What happens when you add three numbers together? Will your answer be odd or even? How do you know?

This challenging activity involves finding different ways to distribute fifteen items among four sets, when the sets must include three, four, five and six items.

Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.

First Connect Three game for an adult and child. Use the dice numbers and either addition or subtraction to get three numbers in a straight line.

If you hang two weights on one side of this balance, in how many different ways can you hang three weights on the other side for it to be balanced?

There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?

Can you find the chosen number from the grid using the clues?

Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.

In this matching game, you have to decide how long different events take.

There are seven pots of plants in a greenhouse. They have lost their labels. Perhaps you can help re-label them.

In this calculation, the box represents a missing digit. What could the digit be? What would the solution be in each case?