Working systematically

problem

Island Hopping

Age

11 to 14

Challenge level

1 out of 3

What is the smallest number of ferry trips that Neda needs to take to visit all four islands and return to the mainland?
problem

Grid Without Lines

Age

11 to 14

Challenge level

1 out of 3

Can you remove the least number of points from this diagram, so no three of the remaining points are in a straight line?
problem

Kept Apart

Age

11 to 14

Challenge level

1 out of 3

The squares of this grid contain one of the letters P, Q, R and S. Can you complete this square so that touching squares do not contain the same letter? How many possibilities are there?
problem

Fruit Line-Up

Age

11 to 14

Challenge level

1 out of 3

This grocer wants to arrange his fruit in a particular order, can you help him?
problem

Colourful Tiles

Age

11 to 14

Challenge level

1 out of 3

Weekly Problem 21 - 2011
How many ways can you paint this wall with four different colours?
problem

Mini-Sudoku

Age

11 to 14

Challenge level

1 out of 3

How many ways are there of completing the mini-sudoku?
problem

Magic Error

Age

11 to 14

Challenge level

1 out of 3

Two of the numbers in a 4×4 magic square have been swapped. Can you work out the sum of these numbers?
problem

Subtracting to 2008

Age

11 to 14

Challenge level

1 out of 3

Can you work out the sum of the missing digits in this subtraction?
problem

Isometric Rhombuses

Age

11 to 14

Challenge level

1 out of 3

Weekly Problem 31 - 2016
The diagram shows a grid of $16$ identical equilateral triangles. How many rhombuses are there made up of two adjacent small triangles?
problem

Half and Half

Age

11 to 14

Challenge level

1 out of 3

Two of the four small triangles are to be painted black. In how many ways can this be done?