They've posted great images on how to count in the language we're gonna call "Pit."
"Numerical hand signals are generally constant throughout all trading floors but slight variations are made with figures greater than 99," writes Trading Pit History's Ryan Carlson. "Price is displayed away from the body and the quantity is displayed close to the face. Generally price is displayed before quantity ("price on quantity") to buy and it's the opposite to sell ("quantity at price")."
It's a relatively sophisticated.
What follows are signals for the numbers 1 through 10 - in reverse order - using the signals employed on the Chicago Mercantile Exchange (CME) floor.