To put on “The Fifty Leaping Lizards Show!,” you need fifty star-struck leaping lizards. Where will they all come from? The first five are found lounging in bunk beds, but the next five arrive in theatrical style, riding unicycles and juggling. The next five are speed-demons in race-cars, followed by five more in a hot-air balloon. Colorful graphics keeps track of the count, first by showing how counting by 5s works, and then showing how counting by 10s is related: Kids can easily see how each group of 10 lizards divides into two groups of 5. Will there be enough lizards by show time? Counting by 5s and 10s is an important skill that helps children master multiplication facts, tell time, and count money. Used with permission from Stuart J. Murphy.