A game that tests your understanding of remainders.
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
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.
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?"
Given the products of adjacent cells, can you complete this Sudoku?
This package contains a collection of problems from the NRICH
website that could be suitable for students who have a good
understanding of Factors and Multiples and who feel ready to take
on some. . . .
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.
Given the products of diagonally opposite cells - can you complete this Sudoku?
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?
Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?
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.
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
For this challenge, you'll need to play Got It! Can you explain the strategy for winning this game with any target?
The clues for this Sudoku are the product of the numbers in adjacent squares.
List any 3 numbers. It is always possible to find a subset of
adjacent numbers that add up to a multiple of 3. Can you explain
why and prove it?
Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?
A mathematician goes into a supermarket and buys four items. Using
a calculator she multiplies the cost instead of adding them. How
can her answer be the same as the total at the till?
A three digit number abc is always divisible by 7 when 2a+3b+c is divisible by 7. Why?
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...
Rectangles are considered different if they vary in size or have different locations. How many different rectangles can be drawn on a chessboard?
Make a set of numbers that use all the digits from 1 to 9, once and
once only. Add them up. The result is divisible by 9. Add each of
the digits in the new number. What is their sum? Now try some. . . .
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.
Find some examples of pairs of numbers such that their sum is a
factor of their product. eg. 4 + 12 = 16 and 4 × 12 = 48 and
16 is a factor of 48.
A game in which players take it in turns to choose a number. Can you block your opponent?
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?
How many integers between 1 and 1200 are NOT multiples of any of
the numbers 2, 3 or 5?
Helen made the conjecture that "every multiple of six has more
factors than the two numbers either side of it". Is this conjecture
Explain why the arithmetic sequence 1, 14, 27, 40, ... contains many terms of the form 222...2 where only the digit 2 appears.
Find the frequency distribution for ordinary English, and use it to help you crack the code.
Is there an efficient way to work out how many factors a large number has?
Can you find any perfect numbers? Read this article to find out more...
Follow this recipe for sieving numbers and see what interesting patterns emerge.
You are given the Lowest Common Multiples of sets of digits. Find
the digits and then solve the Sudoku.
Can you find a way to identify times tables after they have been shifted up?
The puzzle can be solved by finding the values of the unknown digits (all indicated by asterisks) in the squares of the $9\times9$ grid.
Have you seen this way of doing multiplication ?
A collection of resources to support work on Factors and Multiples at Secondary level.
Which pairs of cogs let the coloured tooth touch every tooth on the
other cog? Which pairs do not let this happen? Why?
Do you know a quick way to check if a number is a multiple of two? How about three, four or six?
What can you say about the values of n that make $7^n + 3^n$ a multiple of 10? Are there other pairs of integers between 1 and 10 which have similar properties?
What is the remainder when 2^2002 is divided by 7? What happens
with different powers of 2?
Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.
Some 4 digit numbers can be written as the product of a 3 digit
number and a 2 digit number using the digits 1 to 9 each once and
only once. The number 4396 can be written as just such a product.
Can. . . .
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
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!?
Make a line of green and a line of yellow rods so that the lines
differ in length by one (a white rod)
Consider numbers of the form un = 1! + 2! + 3! +...+n!. How many such numbers are perfect squares?
Prove that if the integer n is divisible by 4 then it can be written as the difference of two squares.
Find the highest power of 11 that will divide into 1000! exactly.
How many numbers less than 1000 are NOT divisible by either: a) 2
or 5; or b) 2, 5 or 7?