Undetermined coefficient method, collocation method, elimination method, fruit holding method, disproof method, elimination method, method of substitution, classification discussion method, mathematical induction method, drawing method, analogy method, transformation method, reduction method, induction method, generalization method, guessing idea method, equation method, function method, same method,

Keywords difference method, commercial method, summation method, quadrature method, whole substitution method, reduction method, mirror image method, coordinate method, complete induction method,

Incomplete induction, formula, factorization.