a=positive because if he get some of the negatives then the number will either turn 0 or negative and has to go inthe pile
b=-0.3or-0.4or-0.5
-0.2-0.3=0.1
-0.2-0.4=0.2
-0.2-0.5=0.3
c=-0.1or-0.2
-0.2-0.1=-0.1
-0.2-0.2=0
one is negative and the other is 0 so they must go back in the pile