Prime numbers
game
Favourite
Dicey array
Watch the video of this game being played. Can you work out the rules? Which dice totals are good to get, and why?
problem
Favourite
Sieve of eratosthenes
Age
11 to 14
Challenge level
Follow this recipe for sieving numbers and see what interesting patterns emerge.
problem
Favourite
Factors and multiples puzzle
Age
11 to 14
Challenge level
Using your knowledge of the properties of numbers, can you fill all the squares on the board?
problem
Favourite
Round and round the circle
Age
7 to 11
Challenge level
What happens if you join every second point on this circle? How about every third point? Try with different steps and see if you can predict what will happen.
problem
Favourite
Factor lines
Age
7 to 14
Challenge level
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
problem
Favourite
Two primes make one square
Age
7 to 11
Challenge level
Can you make square numbers by adding two prime numbers together?
problem
Favourite
Em'power'ed
Age
16 to 18
Challenge level
Find the smallest numbers a, b, and c such that: a^2 = 2b^3 = 3c^5
What can you say about other solutions to this problem?
problem
Favourite
Fac-finding
Age
14 to 16
Challenge level
Lyndon chose this as one of his favourite problems. It is
accessible but needs some careful analysis of what is included and
what is not. A systematic approach is really helpful.
problem
Favourite
How much can we spend?
Age
11 to 14
Challenge level
A country has decided to have just two different coins, 3z and 5z
coins. Which totals can be made? Is there a largest total that
cannot be made? How do you know?