Nikolaus Home Registration Participants Program Puzzle

[Explanation] [Get Another Puzzle]

Given numbers: 1, 2, 5, 6 Result of expression: 9 Number of possible orderings and choices of operators:

Given numbers: 2, 3, 4, 9 Result of expression: 15 Number of possible orderings and choices of operators:

Given numbers: 1, 2, 3, 6 Result of expression: 15 Number of possible orderings and choices of operators:

Questions and suggestions to Frank.Luebeck@Math.RWTH-Aachen.De.