Odd and even numbers

problem

Sets of Four Numbers

Age

7 to 11

Challenge level

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?
problem

Crossings

Age

7 to 11

Challenge level

In this problem we are looking at sets of parallel sticks that cross each other. What is the least number of crossings you can make? And the greatest?
game

Part the Piles

Age

7 to 11

Challenge level

Try to stop your opponent from being able to split the piles of counters into unequal numbers. Can you find a strategy?
problem

Seven Flipped

Age

7 to 11

Challenge level

Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.
problem

Magic Crosses

Age

7 to 14

Challenge level

Can you find examples of magic crosses? Can you find all the possibilities?
problem

Neighbourly Addition

Age

7 to 14

Challenge level

I added together some of my neighbours' house numbers. Can you explain the patterns I noticed?
problem

Prime Magic

Age

7 to 16

Challenge level

Place the numbers 1, 2, 3,..., 9 one on each square of a 3 by 3 grid so that all the rows and columns add up to a prime number. How many different solutions can you find?
problem

Great Granddad

Age

11 to 14

Challenge level

Great Granddad is very proud of his telegram from the Queen congratulating him on his hundredth birthday and he has friends who are even older than he is... When was he born?
game

Femto

Age

14 to 16

Challenge level

A new card game for two players.
game

Femto: Follow Up

Age

14 to 16

Challenge level

Follow-up to the February Game Rules of FEMTO.