Cognitive flexibility increases when there are multiple viewpoints, perspectives, and points of view about a phenomenon. It also increases when there multiple layers of knowledge that interconnect facts, rules, skills, procedures, plans, and deep conceptual principles. The cognitive complexity and multiple viewpoints are helpful when learners face tasks that have unique complexities that cannot be anticipated proactively. For example, mathematics has the layers of facts (2 + 3 = 5), algebraic procedures, and deep mathematical concepts that need to be linked and coordinated. Cognitive flexibility is achieved by trying to solve a large variety of problems and by training that links these different layers.