You're stuck in the past. Kids need to count change less and less everyday. That's the point of the TED talk. Let's start teaching children in accordance with what they'll need in the future, not on what your generation needs. I'm 51 and I can't remember the last time I paid cash in a store or restaurant.
You are at the till in a restaurant, about to pay with debit.
The total is $84.17 and you want to tip through the debit
machine and have the total equal exactly $100. You have
about four seconds to do the math in your head before
you look like a retard. Go!!
I usually pay with debit also, but almost always tip in cash,
as it's nobodies business (Revenue Canada) how much I
leave as a tip for our wait staff....