With an elephant on one end of the teeter-totter, it takes a lot of animals on the other side--and one child--before the teeter-totter will start to move up and down.

Two mice make a teeter-totter. They're balancing just fine, but then along comes a frog. Can they make room for one more friend on their teeter-totter? What about two? What about more? But then a big bird comes along and wants to play too. Better watch out!