Crack the Safe: Level 3
Level 3 is very similar to Levels 1 and 2...but tougher! There is one important difference: there are 4 digits in each combination. This adds a bit more complexity, and requires an extra level of reasoning for the solution process.
Inside, you will find 30 unique puzzles, each containing a 4-digit combination lock, and the difficulty increases from start to finish.
Full description below.
This book consists of 30 puzzles, as well as detailed solution tutorials. Each puzzle involves finding the correct combination for a combination lock, given certain clues regarding the "closeness" of some incorrect guesses.
The puzzles progress in order from easiest to more difficult. All lock combinations in this Level 3 book contain four digits. Repeated digits are not allowed.