Jim Hampton wrote:

I've caught kids making mistakes, even with a calculator, when making
change. One kid had to get the manager to figure it out when she punched a
button showing I paid exact change (no, I gave her a twenty for a purchase a
bit over $12.00). I watched the manager show her how to fix it. Um ...
$21.00? No, I don't think so. He pushed a few more buttons. Over $32.00?

I finally suggested that he clear the whole thing and try again. Meanwhile,
I knew exactly what my change should have been. Another kid at the pharmacy
one time made the same error. He ran it on a calculator and gave me my
change. I gave him a penny and told him to hold on to it as his drawer was
going to be short one cent (assuming he didn't screw up another order in a
different column).

The difference between the older and newer generation is, if the new
generation does calculations by long hand, then use a calculator to see
if their cyphering was correct. The older generation cyphers on a
calculator, the does it by long hand to see if the calculator is correct.