The Treasure Map

Problem

Captain Blackheart had buried his treasure and committed the biggest sin a pirate can commit – he had lost his treasure map! But all was not lost. His trusty crew all remembered different bits of the map.

"I remember drawing it with 5 squares each way", said the Captain. ("He can’t count over 6", the cabin boy John said.)

"There was a row of three trees running due East from the square (1,1)", Peg Leg Pete said. "You put each one of them on a different square."

"Weren’t there four granite boulders going due South from (5,5)?" John asked. "I think you put one of them each in a square too."

"Ah!. Now I remember!" yelled the Captain. "I buried the treasure half way between the first rock and the most western tree!"

Where is the treasure?

Teaching sequence

1. Set the scene for the problem. This could be done by displaying a 5x5 grid (burnt at the edges) and telling the class that this is the map that the pirate lost and when it was found no details remained.
2. Discuss the details that might be found on a pirates map – landmarks, compass directions (N,S,E,W).
3. Pose the problem.
4. Brainstorm for ways to solve the problem – (draw, use equipment).
5. As the students work on the problem check that they understand the use of grid references and the compass directions.
6. Wait until all the students have located the treasure before sharing solutions.

Extension to the problem

Write clues for their own treasure map. Post as a challenge for others to solve.

Solution

We have put all the information from the story on the map below.

The square that the treasure is in is (3,3).