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.
Find the smallest whole number which, when mutiplied by 7, gives a product consisting entirely of ones.
This Sudoku, based on differences. Using the one clue number can you find the solution?
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...
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
A particular technique for solving Sudoku puzzles, known as "naked pair", is explained in this easy-to-read article.
Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.
Given the products of adjacent cells, can you complete this Sudoku?
This Sudoku requires you to do some working backwards before working forwards.
Follow the clues to find the mystery number.
How many different differences can you make?
A cinema has 100 seats. Show how it is possible to sell exactly 100 tickets and take exactly £100 if the prices are £10 for adults, 50p for pensioners and 10p for children.
Find the values of the nine letters in the sum: FOOT + BALL = GAME
Replace the letters with numbers to make the addition work out correctly. R E A D + T H I S = P A G E
Countries from across the world competed in a sports tournament. Can you devise an efficient strategy to work out the order in which they finished?
By selecting digits for an addition grid, what targets can you make?
Four small numbers give the clue to the contents of the four surrounding cells.
Make your own double-sided magic square. But can you complete both sides once you've made the pieces?
The clues for this Sudoku are the product of the numbers in adjacent squares.
Each clue in this Sudoku is the product of the two numbers in adjacent cells.
How many solutions can you find to this sum? Each of the different letters stands for a different number.
The letters in the following addition sum represent the digits 1 ... 9. If A=3 and D=2, what number is represented by "CAYLEY"?
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?
If you take a three by three square on a 1-10 addition square and multiply the diagonally opposite numbers together, what is the difference between these products. Why?
This pair of linked Sudokus matches letters with numbers and hides a seasonal greeting. Can you find it?
Can you work out some different ways to balance this equation?
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.
Zumf makes spectacles for the residents of the planet Zargon, who have either 3 eyes or 4 eyes. How many lenses will Zumf need to make all the different orders for 9 families?
Can you substitute numbers for the letters in these sums?
Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.
The planet of Vuvv has seven moons. Can you work out how long it is between each super-eclipse?
A monkey with peaches, keeps a fraction of them each day, gives the rest away, and then eats one. How long can his peaches last?
Tom and Ben visited Numberland. Use the maps to work out the number of points each of their routes scores.
You need to find the values of the stars before you can apply normal Sudoku rules.
How could you put these three beads into bags? How many different ways can you do it? How could you record what you've done?
60 pieces and a challenge. What can you make and how many of the pieces can you use creating skeleton polyhedra?
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?
Have a go at balancing this equation. Can you find different ways of doing it?
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.
Each of the main diagonals of this sudoku must contain the numbers 1 to 9 and each rectangle width the numbers 1 to 4.
The items in the shopping basket add and multiply to give the same amount. What could their prices be?
Can you complete this calculation by filling in the missing numbers? In how many different ways can you do it?
There are 4 jugs which hold 9 litres, 7 litres, 4 litres and 2 litres. Find a way to pour 9 litres of drink from one jug to another until you are left with exactly 3 litres in three of the jugs.
Given the products of diagonally opposite cells - can you complete this Sudoku?
Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.
On my calculator I divided one whole number by another whole number and got the answer 3.125. If the numbers are both under 50, what are they?
This magic square has operations written in it, to make it into a maze. Start wherever you like, go through every cell and go out a total of 15!
The letters of the word ABACUS have been arranged in the shape of a triangle. How many different ways can you find to read the word ABACUS from this triangular pattern?
A Sudoku that uses transformations as supporting clues.
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?