I went to the bank today to deposit a collection of $1 and $2 coins I had been collecting in a savings tin.
The young cashier sorted my coins into bag, then weighed them to come up with the totals of $270 for the $2 coins and $48 for the $1 coins. The cashier then had to work out what $270 +$48 actually came to, she got out a pen and tried the addition on paper. After some patient waiting I notice she had somehow come up with $715 and was no closer to an acceptable solution, so eventually the trusty computer was fired up and the problem was solved.
I’m sure I only had $312 in that tin as well.