Exploring and noticing

problem

3388

Age

11 to 14

Challenge level

Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.
problem

Four Coloured Lights

Age

11 to 14

Challenge level

Imagine a machine with four coloured lights which respond to different rules. Can you find the smallest possible number which will make all four colours light up?
problem

Pair Sums

Age

11 to 14

Challenge level

Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?
problem

Top-Heavy Pyramids

Age

11 to 14

Challenge level

Use the numbers in the box below to make the base of a top-heavy pyramid whose top number is 200.
problem

Who's Who?

Age

11 to 16

Challenge level

Can you solve the clues to find out who's who on the friendship graph?
problem

Do Rare Events Happen?

Age

11 to 16

Challenge level

I'd be very surprised if I had three children all with the same birthday, but I read in the paper that it happened to one family...
game

Last Biscuit

Age

11 to 18

Challenge level

Can you find a strategy that ensures you get to take the last biscuit in this game?
problem

The Perforated Cube

Age

14 to 16

Challenge level

A cube is made from smaller cubes, 5 by 5 by 5, then some of those cubes are removed. Can you make the specified shapes, and what is the most and least number of cubes required ?
problem

Electric Kettle

Age

14 to 16

Challenge level

Explore the relationship between resistance and temperature
problem

Day of the Triffids

Age

14 to 16

Challenge level

Jasmine buys three different types of plant. How many triffids did she buy?