Two motorboats travelling up and down a lake at constant speeds leave opposite ends A and B at the same instant, passing each other, for the first time 600 metres from A, and on their return, 400. . . .
A spider is sitting in the middle of one of the smallest walls in a room and a fly is resting beside the window. What is the shortest distance the spider would have to crawl to catch the fly?
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?
An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Four bags contain a large number of 1s, 3s, 5s and 7s. Pick any ten numbers from the bags above so that their total is 37.
How many solutions can you find to this sum? Each of the different letters stands for a different number.
Can you find six numbers to go in the Daisy from which you can make all the numbers from 1 to a number bigger than 25?
Different combinations of the weights available allow you to make different totals. Which totals can you make?
On the graph there are 28 marked points. These points all mark the vertices (corners) of eight hidden squares. Can you find the eight hidden squares?
Show that is it impossible to have a tetrahedron whose six edges have lengths 10, 20, 30, 40, 50 and 60 units...
How many winning lines can you make in a three-dimensional version of noughts and crosses?
Ben passed a third of his counters to Jack, Jack passed a quarter of his counters to Emma and Emma passed a fifth of her counters to Ben. After this they all had the same number of counters.
Five children went into the sweet shop after school. There were choco bars, chews, mini eggs and lollypops, all costing under 50p. Suggest a way in which Nathan could spend all his money.
There are four children in a family, two girls, Kate and Sally, and two boys, Tom and Ben. How old are the children?
Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?
Use the differences to find the solution to this Sudoku.
Can you see how to build a harmonic triangle? Can you work out the next two rows?
Explore the effect of reflecting in two parallel mirror lines.
My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?
Can you describe this route to infinity? Where will the arrows take you next?
Which set of numbers that add to 10 have the largest product?
Explore the effect of combining enlargements.
How many more miles must the car travel before the numbers on the milometer and the trip meter contain the same digits in the same order?
How many different symmetrical shapes can you make by shading triangles or squares?
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
Square numbers can be represented as the sum of consecutive odd numbers. What is the sum of 1 + 3 + ..... + 149 + 151 + 153?
A 2 by 3 rectangle contains 8 squares and a 3 by 4 rectangle contains 20 squares. What size rectangle(s) contain(s) exactly 100 squares? Can you find them all?
Can you find an efficient method to work out how many handshakes there would be if hundreds of people met?
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?
Can you work out the dimensions of the three cubes?
A game for 2 or more people, based on the traditional card game Rummy. Players aim to make two `tricks', where each trick has to consist of a picture of a shape, a name that describes that shape, and. . . .
A square of area 40 square cms is inscribed in a semicircle. Find the area of the square that could be inscribed in a circle of the same radius.
If you move the tiles around, can you make squares with different coloured edges?
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
What is the area of the quadrilateral APOQ? Working on the building blocks will give you some insights that may help you to work it out.
Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
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?
Find a cuboid (with edges of integer values) that has a surface area of exactly 100 square units. Is there more than one? Can you find them all?
Start with two numbers and generate a sequence where the next number is the mean of the last two numbers...
The clues for this Sudoku are the product of the numbers in adjacent squares.
Imagine you have a large supply of 3kg and 8kg weights. How many of each weight would you need for the average (mean) of the weights to be 6kg? What other averages could you have?
Can you maximise the area available to a grazing goat?
Can all unit fractions be written as the sum of two unit fractions?
Manufacturers need to minimise the amount of material used to make their product. What is the best cross-section for a gutter?
Explore when it is possible to construct a circle which just touches all four sides of a quadrilateral.
Is there an efficient way to work out how many factors a large number has?
Two ladders are propped up against facing walls. The end of the first ladder is 10 metres above the foot of the first wall. The end of the second ladder is 5 metres above the foot of the second. . . .
A plastic funnel is used to pour liquids through narrow apertures. What shape funnel would use the least amount of plastic to manufacture for any specific volume ?
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.