Robert Downey Jr. has been all over the publicity circuit to hype up The Avengers. Browsing his various photo ops, we noticed an unexpected constant: When waving to crowds or paparazzi, RDJ often holds up a different number of fingers. Is this a signal? Is he silently alerting us to his prediction for his film’s worldwide box office, in billions? No, we have decided that what he’s actually doing is using his red carpet time to also teach today’s grade schoolers how to do simple arithmetic. By combining some of his brandished numbers, you get a wonderful math primer that kids can learn from … while also begging their parents to take them to see The Avengers, in 3-D! Sesame Street has nothing on Iron Man.