# Codebreaking: Mastery and Problem Solving

#### Low Threshold High Ceiling Tasks

Low Threshold High Ceiling (LTHC) tasks were popularised by the mathematician Jo Boaler and have also been promoted by NRICH. Let’s get into the activities!

Problem Solving Using an Elimination Method.

In all five puzzles, there are statements given with a corresponding 3 digit number. Students will have to read the statements that accompany the numbers and come up with the logical answer to find the correct 3 digit number to open the lock.

You can find the answers to the puzzles at the very bottom of this post.

The puzzles are written in a way that your students may be unfamiliar with, so they are a great way to get your students read the questions carefully and developing their logic skills, so they’ll have to concentrate!

If you are teaching younger students you might want to simplify puzzle 1 and 2 by supplying one of the correct digits. Puzzles 3, 4 and 5 get progressively harder and can be extended by asking for a written method to solve the puzzles. The last puzzle is completely open ended but students can try and re-write one of the earlier puzzles.

Click the image below to download the Codebreaking activity or alternatively you can click here!