The development of reasoning ability is one of the major goals of education, and mathematics as reasoning is one of the objectives of the standards created by the National Council of Teachers of Mathematics. As students develop reasoning power, they progress toward the highest levels of Bloom's taxonomy and encounter the need to synthesize or prove that what they reasoned will always be true. Proofs may take many forms; an argument using prose, a logic argument, an indirect proof which assumes a statement is false and reaches a contradiction, or a proof by mathematical induction. Proof is an important part of the reasoning process; thus curriculum materials should include simple proofs starting in the intermediate grades.