Maths Week Puzzles 2016

Once again the Irish Times will be running puzzles for Maths Week.

Each day will at 12 pm we will give you the answer and the method here.



Arrange the numbers 1-19 in the grid below so that each row, column and diagonal adds to 38.

You can only use each number once and every number must be used.

Click here for the solution.

Teacher's note: the difficulty of this puzzle can be altered by providing some of the numbers as a starting point. Logic and reasoning will then allow pupils to complete the puzzle!

The Handshake Puzzle

Arturas, Liam, Nina and Samira meet up. Each person shakes hands with every other person once.

How many handshakes are there in total?


Click here for the solution.

How many messages?

Pete, Sarah, Matt, Amy and Luke are all friends. Each of them sends one text message to each other person.

How many messages are sent in total?


Click here for the solution.

World Cup Qualifiers

There are 6 teams in a group. Each team plays every other team twice.

How many games are there in total?


Click here for the solution.

Attacking the Castle


A square medieval castle sits on a square island surrounded by a square moat was under siege. All around the island, there is a 5 metre wide water moat. There's ground on the other side to rest the bridge on (if you can get it to stretch that far).

Expanding Car Park


A client wants to double the size of his car park (shown below). He insists on retaining a square shape and as many of the trees as possible.

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