Learn English – Alternative to “minuend” and “subtrahend”

In math, I just learned that when performing subtraction, the terms for each number are as follows:

minuend − subtrahend = difference

I have never heard of minuend and subtrahend before, and I'm fairly certain the majority of people I encounter have never heard these terms before either. Is there a better alternative to these two words?

Context:
I'm writing some software that subtracts a set of items from another set of items, such as in this math.SE question. I need to name these two sets of items so they are easy to understand for an average user, or a future developer working on the same software.

Edit:

For those who want to see code, I'm writing a PowerShell cmdlet that would be used like so:

Get-Difference -Minuend "a.csv" -Subtrahend "b.csv"

and in the code I may write something like:

var minuendData = readFile(minuendFilePath)

Currently I have the following comment at the top of my code:

// If you don't know what a minuend or a subtrahend is, then shame on you!
// http://dictionary.reference.com/browse/minuend
// http://dictionary.reference.com/browse/subtrahend

I could just use something like "A" or "B" but that is not as descriptive as I'd like it to be.