Easy
7
+12
×4
−8
HALVE
+2
÷9
SQUARE
−4
÷6
Medium
55
DOUBLE
−2
÷9
SQUARE
×1/3
−13
×3
−1
×1/4
Hard
36
−1
×11/5
HALVE
−3
SQUARE
×25%
+10
×11/13
−13
There are two versions that can be printed, a default one, and one that requires less ink (no objectives or rules, and no lines).