Correct Change

So I'd hopped on register to back up cashier for our main cashier.

Which isn't bad. 
I was helping an older lady out with her purchase.

And she'd given me cash.

And I'd put in the amount she'd given me and already hit enter....
When she was like "Oh I have two pennies I can give you!" 

>.< Can I just say I don't like it when people give me change after I already put in the first amount of money they gave me? 
Because I don't.

Because it means I then have to do quick math to make sure I give the customer the correct change back.
Most of the time it's easy. They just gave me the change so they wouldn't get any change back. Therefore I just give them bills. 

This time though.

I owed the woman 53 cents. 

And she was like "Here, I have two pennies."

And I was like. O.o 
Well...crap.
(keep in mind I'm also tired from not enough sleep and a long work day) 

So I couldn't figure out if I now owed her 55 cents or 51 cents.

I figured it was the 55 cents. 
But was still processing to make sure I was adding this correctly.

When the woman was like: *exhales* You kids and your dependence on technology! It's Fifty-five cents you owe me now! 

....well....excuse me for liking having things easy. *shakes head* 
Though seriously. It was more of the fact that I'm tired than anything else.
I can do math.
Most days. 

Just not  in that moment. lol.

But hey.
She got her change.

Though I am still wondering if I gave her the right amount.....it makes the most sense....but still I do wonder...

-Sarnic Dirchi