bang 

In left inlet: Performs the subtraction with the numbers currently stored. If there is no argument,  initially holds 0. 
int 
input [int]

In left inlet: The number in the right inlet is subtracted from the number, and the result is sent out the outlet. 
(inlet1) 
valuesubtractedfrom [int]

In right inlet: The number is stored, to be subtracted from, by a number received in the left inlet. 
float 
input [float]

Converted to int, unless  has a float argument. 
set 
setinput [int]

Sets the number to be subtracted without causing output (bang will output it). 
list 
input [list]

In left inlet: The first number is subtracted from the second number, and the result is sent out the outlet. 