Teach numbers through games and everyday experiences. Then count the girls. Then count them. There are zero snakes in our room. You get the idea.
Children usually like to participate by coming up with their own outrageous suggestions.
Also, make a zero with your thumb and finger or draw zero in the air. Place old calendars in your Pre-Math Center and let children place a small object on all the 0's they see. By the way, if you buy those cartons of liquid creamer for your coffee that comes with a small lid opening, save those lids as they make perfect tokens for games such as this one. Collect enough of them and they can become a color sorting game in themselves. Keep the posterboard pieces in sheet protectors for easy lamination and store them with the items you drew around.