When the focus is on developing a method for solving a computation and on describing that process to others, students are forced to think more about what they did and why they did it than about whether they got the right answer. Students still want to get the right answer, of course, but they no longer cease thinking about the process when they discover whether their answer was right or wrong. In PreK, the groundwork for computation ability includes free exploration of materials and development of communication skills about attributes and classification. On the kindergarten level, groundwork for later computation ability includes developing a strong number sense. In particular, the ability to arrange a certain number of objects in various subgroups underlies computation.
Kindergartners are able to see that groups can be composed of subgroups.
First-grade students begin combining and separating groups of objects for addition and subtraction. Addition and subtraction facts can be searched for patterns. Students learn to describe the process they used in adding and subtracting and to listen to the processes used by others. At the second-grade level, adding and subtracting abilities extend to larger numbers and more complex methods of computing an answer. The focus is on flexibility of methods.