See also: Matching topics (16) Matching titles (121)
How Steep Is the Slope?
Stage: 3 Challenge Level: 
On the grid provided, we can draw lines with different gradients. How many different gradients can you find? Can you arrange them in order of steepness?
Surprising Transformations
Stage: 3 Challenge Level:
I took the graph y=4x+7 and performed four transformations. Can you find the order in which I could have carried out the transformations?
The Greedy Algorithm
Stage: 3 Challenge Level:
The Egyptians expressed all fractions as the sum of different unit fractions. The Greedy Algorithm might provide us with an efficient way of doing this.
Keep it Simple
Stage: 3 Challenge Level:
Can all unit fractions be written as the sum of two unit fractions?
Translating Lines
Stage: 3 Challenge Level:
Investigate what happens to the equation of different lines when you translate them. Try to predict what will happen. Explain your findings.
Countdown
Stage: 2 and 3 Challenge Level:
Here is a chance to play a version of the classic Countdown Game.
Reflecting Lines
Stage: 3 Challenge Level:
Investigate what happens to the equations of different lines when you reflect them in one of the axes. Try to predict what will happen. Explain your findings.
At Right Angles
Stage: 3 Challenge Level:
Can you decide whether two lines are perpendicular or not? Can you do this without drawing them?
2009 Challenge
Stage: 3, 4 and 5 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.
The Remainders Game
Stage: 2 and 3 Challenge Level:
A game that tests your understanding of remainders.
Power Mad!
Stage: 3 Challenge Level:
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
Hidden Dimensions
Stage: 3 Challenge Level:
Can you find rectangles where the value of the area is the same as the value of the perimeter?
Elevenses
Stage: 3 Challenge Level:
How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?
Searching for Mean(ing)
Stage: 3 Challenge Level:
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?
Cops and Robbers
Stage: 2 and 3 Challenge Level:
Can you find a reliable strategy for choosing coordinates that will locate the robber in the minimum number of guesses?
Eight Hidden Squares
Stage: 2 and 3 Challenge Level:
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?
M, M and M
Stage: 3 Challenge Level:
If you are given the mean, median and mode of five positive whole numbers, can you find the numbers?
Understanding Hypotheses
Stage: 3, 4 and 5
This article explores the process of making and testing hypotheses.
Which Spinners?
Stage: 3 Challenge Level:
Which spinners were used to generate these frequency charts?
Data Collection Tool
Stage: 3 and 4 Challenge Level:
An interactivity that enables you collect data from an experiment with true/false outcomes.
All in a Jumble
Stage: 3 Challenge Level:
My measurements have got all jumbled up! Swap them around and see if you can find a combination where every measurement is valid.
Weights
Stage: 3 Challenge Level:
Different combinations of the weights available allow you to make different totals. Which totals can you make?
Adding and Subtracting Positive and Negative Numbers
Stage: 3 and 4
How can we help students make sense of addition and subtraction of negative numbers?
Consecutive Negative Numbers
Stage: 3 Challenge Level:
Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?
First Connect Three
Stage: 2 and 3 Challenge Level:
The idea of this game is to add or subtract the two numbers on the dice and cover the result on the grid, trying to get a line of three. Are there some numbers that are good to aim for?
Difference Sudoku
Stage: 3 and 4 Challenge Level:
Use the differences to find the solution to this Sudoku.
More Twisting and Turning
Stage: 3 Challenge Level:
It would be nice to have a strategy for disentangling any tangled ropes...
Twisting and Turning
Stage: 3 Challenge Level:
Take a look at the video and try to find a sequence of moves that will take you back to zero.
Walking Around a Cube
Stage: 3 and 4 Challenge Level:
Find the length along the shortest path passing through certain points on the cube.
Matchless
Stage: 3 and 4 Challenge Level:
There is a particular value of x, and a value of y to go with it, which make all five expressions equal in value, can you find that x, y pair ?
Parallel Lines
Stage: 3 Challenge Level:
How does the position of the line affect the equation of the line? What can you say about the equations of parallel lines?
Integrated Product Sudoku
Stage: 3 and 4 Challenge Level:
This Sudoku puzzle can be solved with the help of small clue-numbers on the border lines between pairs of neighbouring squares of the grid.
Integrated Sums Sudoku
Stage: 3 and 4 Challenge Level:
The puzzle can be solved with the help of small clue-numbers which are either placed on the border lines between selected pairs of neighbouring squares of the grid or placed after slash marks on. . . .
Spaces for Exploration
Stage: 3 and 4
Alf Coles writes about how he tries to create 'spaces for exploration' for the students in his classrooms.
Fractions Jigsaw
Stage: 3 Challenge Level:
A jigsaw where pieces only go together if the fractions are equivalent.
Cunning Card Trick
Stage: 3 Challenge Level:
Delight your friends with this cunning trick! Can you explain how it works?
...on the Wall
Stage: 3 Challenge Level:
Explore the effect of reflecting in two intersecting mirror lines.
Mirror, Mirror...
Stage: 3 Challenge Level:
Explore the effect of reflecting in two parallel mirror lines.
Transformation Game
Stage: 3 Challenge Level:
Why not challenge a friend to play this transformation game?
Factors and Multiples Puzzle
Stage: 3 Challenge Level:
A challenge that requires you to apply your knowledge of the properties of numbers. Can you fill all the squares on the board?
Intersection Sums Sudoku
Stage: 2, 3 and 4 Challenge Level:
A Sudoku with clues given as sums of entries.
Diagonal Sums Sudoku
Stage: 2, 3 and 4 Challenge Level:
Solve this Sudoku puzzle whose clues are in the form of sums of the numbers which should appear in diagonal opposite cells.
Product Sudoku 2
Stage: 3, 4 and 5 Challenge Level:
Given the products of diagonally opposite cells - can you complete this Sudoku?
More Magic Potting Sheds
Stage: 3 Challenge Level:
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?
Magic Potting Sheds
Stage: 3 Challenge Level:
Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?
Product Sudoku
Stage: 3, 4 and 5 Challenge Level:
The clues for this Sudoku are the product of the numbers in adjacent squares.
Archery
Stage: 3 Challenge Level:
Imagine picking up a bow and some arrows and attempting to hit the target a few times. Can you work out the settings for the sight that give you the best chance of gaining a high score?
Areas of Parallelograms
Stage: 3 Challenge Level:
Can you find the area of a parallelogram defined by two vectors?
Motion Capture
Stage: 3 and 4 Challenge Level:
Explore displacement/time and velocity/time graphs with this mouse motion sensor.
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