RPN. Like those old Hewlett Packard calculators.

"6" "enter" "3" "enter" "4" "+" Answer "13" is displayed.
Back on topic - no vanity plate for me. I don't need the wrath of the hybrid-haters.
Most we can't convert anyway (they have to feel the pain in their own wallets).
One-on-one with a co-worker - I have a much better chance of one of them being open to learning.