I ran into a neat math puzzle where, given some numbers in order and given an expected result, I had to decide which were the mathematic operations to place between the numbers to reach the result. The rules were:

1. Available operations: addition (+), subtraction (-), multiplication (x) & division (:)
2. Multiplication and division took precedence.

For example:

1 [ ] 6 [ ] 2 = 4

The operations to reach the result are + and :, resulting in this solution:

1 + 6 : 2 = 4

After finishing the math puzzle I thought it would be a nice exercise to write a program which found the solutions, so here it is. Have fun!

math-solver:solve-math expects a list of integers, as the arguments to the equation, and another integer, as the result of equation. For example:

(math-solver:solve-math '(1 6 2) 4)
;; "1 + 6 : 2"

Tested only on alisp 10.1.