it means to subtract
I think subtract.
deposit = add withdraw = subtract
Mark up would mean to add. Mark down would mean to subtract.
Total means to Add.
It depends on how the rest of the question is worded. If it says "how many were left," for example, that means to subtract. On the other hand, if it says something like "how many were added," it means to add.
When it says how much more you would subtract the little number from the big number. Hope Im Helpful