The creators of Endless Alphabet and Endless Reader turn their talents to the realm of numbers. This app sneakily teaches so many different math concepts (counting by ones, twos, threes; addition; place value, etc.) and yet it's simple enough for a preschooler to navigate without problems. Each number features a short, humorous animation to illustrate the quantity, which kids will want to watch over and over. The free version gives users access to numbers 1-5 and then in-app purchases give you the opportunity to expand all the way to 100.