Fourth graders advance to new levels in the lesson we're dealing with here. It is the fourth of a sequence of six dealing with the same theme. These develop from Level 2 to Level 5. In the process they involve number concepts at the various Levels and will gradually involve algebraic concepts too. The lessons are Points, Level 1, Names and Numbers, Level 2, Make 4.253, Level 3, Doubling Up, Level 5 and Multiples of a, Level 6.