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...
A student in a maths class was trying to get some information from her teacher. She was given some clues and then the teacher ended by saying, "Well, how old are they?"
Do you know a quick way to check if a number is a multiple of two? How about three, four or six?
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
Given the products of adjacent cells, can you complete this Sudoku?
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.
The clues for this Sudoku are the product of the numbers in adjacent squares.
Play this game and see if you can figure out the computer's chosen number.
Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?
Explain why the arithmetic sequence 1, 14, 27, 40, ... contains many terms of the form 222...2 where only the digit 2 appears.
Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?
Factor track is not a race but a game of skill. The idea is to go round the track in as few moves as possible, keeping to the rules.
Helen made the conjecture that "every multiple of six has more factors than the two numbers either side of it". Is this conjecture true?
Can you explain the strategy for winning this game with any target?
Is there an efficient way to work out how many factors a large number has?
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
Can you find any two-digit numbers that satisfy all of these statements?
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?
Can you find any perfect numbers? Read this article to find out more...
What is the remainder when 2^2002 is divided by 7? What happens with different powers of 2?
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?
Factors and Multiples game for an adult and child. How can you make sure you win this game?
How many numbers less than 1000 are NOT divisible by either: a) 2 or 5; or b) 2, 5 or 7?
Find the number which has 8 divisors, such that the product of the divisors is 331776.
I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?
A number N is divisible by 10, 90, 98 and 882 but it is NOT divisible by 50 or 270 or 686 or 1764. It is also known that N is a factor of 9261000. What is N?
I put eggs into a basket in groups of 7 and noticed that I could easily have divided them into piles of 2, 3, 4, 5 or 6 and always have one left over. How many eggs were in the basket?
Twice a week I go swimming and swim the same number of lengths of the pool each time. As I swim, I count the lengths I've done so far, and make it into a fraction of the whole number of lengths I. . . .
Imagine we have four bags containing numbers from a sequence. What numbers can we make now?
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
Follow this recipe for sieving numbers and see what interesting patterns emerge.
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.
What is the smallest number of answers you need to reveal in order to work out the missing headers?
What is the value of the digit A in the sum below: [3(230 + A)]^2 = 49280A
Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?
I added together the first 'n' positive integers and found that my answer was a 3 digit number in which all the digits were the same...
Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why?
Can you find a way to identify times tables after they have been shifted up or down?
The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?
How many integers between 1 and 1200 are NOT multiples of any of the numbers 2, 3 or 5?
Got It game for an adult and child. How can you play so that you know you will always win?
A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
Find the highest power of 11 that will divide into 1000! exactly.
Can you find a relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?
I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?
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?
When the number x 1 x x x is multiplied by 417 this gives the answer 9 x x x 0 5 7. Find the missing digits, each of which is represented by an "x" .
The five digit number A679B, in base ten, is divisible by 72. What are the values of A and B?
A game in which players take it in turns to choose a number. Can you block your opponent?