I'm having a lot of fun playing Calculator: The Game and decided to write a solver in OCaml.
~/P/o $ ocaml main.ml
Level 11
-8 x11 <<
x11 << -8
Level 12
+8 x10 x10 +8 /2
Level 24
2 5 -5 5 +5
Level 30
1 2 1 2=>3 1=>2 1
1 2 2=>3 1 1=>2 1
1 2 2=>3 2 1=>2 1
1 2 2=>3 1=>2 2 1