> When I go to the grocery store, I usually keep a sum of the price in my head while I pick products. That way I'll know if something is off at the counter. I

> When I go to the grocery store, I usually keep a sum of the price in my head while I pick products. That way I'll know if something is off at the counter. I do the same thing, but it does depend on how much I'm shopping. If its big for the whole family I keep a rounded tally in my head, and use that sum to determine whether or not I look at the actual receipt to see if something was wrong. If on the other hand I'm buying say less than 15 items then I'll keep up with the actual to the cent sums when I'm paying in cash. You get a weird look sometimes when you get to the counter, they say 23.45 and you hand them the money immediately. I've done this ever since I can remember, but growing up in the USA you just had the added step that you needed to know what the sales tax rate was for the area you were currently in, and if you didn't know it then I'd just use a default rate of 8%.