Each clue in this Sudoku is the product of the two numbers in adjacent cells.
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?
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.
Here is a chance to play a version of the classic Countdown Game.
The clues for this Sudoku are the product of the numbers in adjacent squares.
Here is a chance to play a fractions version of the classic Countdown Game.
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?
You can work out the number someone else is thinking of as follows. Ask a friend to think of any natural number less than 100. Then ask them to tell you the remainders when this number is divided by. . . .
Find the smallest whole number which, when mutiplied by 7, gives a product consisting entirely of ones.
Work out Tom's number from the answers he gives his friend. He will only answer 'yes' or 'no'.
Given the products of adjacent cells, can you complete this Sudoku?
56 406 is the product of two consecutive numbers. What are these two numbers?
Play this game and see if you can figure out the computer's chosen number.
6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?
Using the digits 1, 2, 3, 4, 5, 6, 7 and 8, mulitply a two two digit numbers are multiplied to give a four digit number, so that the expression is correct. How many different solutions can you find?
Does this 'trick' for calculating multiples of 11 always work? Why or why not?
Find the highest power of 11 that will divide into 1000! exactly.
Choose any four consecutive even numbers. Multiply the two middle numbers together. Multiply the first and last numbers. Now subtract your second answer from the first. Try it with your own. . . .
This Sudoku requires you to do some working backwards before working forwards.
Can you work out what a ziffle is on the planet Zargon?
This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?
The number 8888...88M9999...99 is divisible by 7 and it starts with the digit 8 repeated 50 times and ends with the digit 9 repeated 50 times. What is the value of the digit M?
After training hard, these two children have improved their results. Can you work out the length or height of their first jumps?
Watch the video of this game being played. Can you work out the rules? Which dice totals are good to get, and why?
The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?
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?
Here is a picnic that Petros and Michael are going to share equally. Can you tell us what each of them will have?
What is the smallest number of answers you need to reveal in order to work out the missing headers?
Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?
Which set of numbers that add to 10 have the largest product?
Find the number which has 8 divisors, such that the product of the divisors is 331776.
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.
This jar used to hold perfumed oil. It contained enough oil to fill granid silver bottles. Each bottle held enough to fill ozvik golden goblets and each goblet held enough to fill vaswik crystal. . . .
What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?
I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?
Your vessel, the Starship Diophantus, has become damaged in deep space. Can you use your knowledge of times tables and some lightning reflexes to survive?
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
Find the product of the numbers on the routes from A to B. Which route has the smallest product? Which the largest?
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?
These pictures and answers leave the viewer with the problem "What is the Question". Can you give the question and how the answer follows?
Look on the back of any modern book and you will find an ISBN code. Take this code and calculate this sum in the way shown. Can you see what the answers always have in common?
Can you arrange 5 different digits (from 0 - 9) in the cross in the way described?
All the girls would like a puzzle each for Christmas and all the boys would like a book each. Solve the riddle to find out how many puzzles and books Santa left.
Number problems at primary level that may require resilience.
Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. . . .
Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?
If you had any number of ordinary dice, what are the possible ways of making their totals 6? What would the product of the dice be each time?
A number game requiring a strategy.
Using the statements, can you work out how many of each type of rabbit there are in these pens?
How many ways can you find to put in operation signs (+ - x Ã·) to make 100?