Boost learners' grasp of number theory with this online math game all about factors and multiples! In Jumpy: Which Factor Does Not Belong?, players will first choose the number that does not belong in the factor list of a given two-digit number, then they will jump from object to object to help Roly make it across the river. This game is a great way to reinforce fourth-grade number sense skills! (Hint: Use the space bar to move Roly through the game.)