Interpreting Division as subtraction Basically, Division is the inverse of multiplication, see this instance:  
5  × 4,
This basically means, adding five four times,
5, 5, 5, 5 added together is 20; 
If division is the inverse of multiplication and multiplication comes from repeated addition, how can we interpret division as repeated subtraction?
Consider:
20/4;
How can we interpret this as the statements in bold above?  
That's the level 1 of confusion, the next is, while taking the word PEPPER:
Total arrangement is given by the formula:    
6!/(3!2!)
How can we interpret the result as above, i.e. with the division interpreted as a series of repeated subtraction?
EDIT: And how do we relate this with the fact that division is breaking things up equally with respect to the denominator? And in this case:
Why isn't 6!-(3!2!)used?

If we want to do some division using subtraction. We have to use successive subtraction until we got zero. And the number of time you subtract is the answer.
In your first case,
20 - 4 = 16
16 - 4 = 12
12 - 4 = 8
8 - 4 = 4
4 - 4 = 0
So we subtract 4 five times so answer is 5
In second case 6! = 720 and 2!3! = 12
So we have to subtract 12 sixty times to get zero so answer is 60.

Edit  -

We can use any operation on factorials directly.
So you have to do 720 - 12 repeatedly.
