To appreciate the role of Level B, one must view it in the context of the Kumon continuum. Preceding Level B are Levels 3A, 2A, and A, which are dedicated to the mastery of addition and subtraction. By the time a student reaches Level B, they have theoretically mastered horizontal addition and subtraction and are moving toward vertical calculations. Level B is fundamentally about the transition to "pencil and paper" calculation methods—specifically, the formal written algorithms for addition and subtraction of larger numbers.
: Mastering the technique of borrowing (regrouping) in 2-digit and 3-digit subtraction. kumon answer book level b math