Korrutusega

Korrutusega is the Estonian expression associated with the arithmetic operation of multiplication. In mathematics, korrutamine is the act of combining two numbers, called factors, to produce a product. The operation is commonly denoted by the symbols × or ·, and in algebra by a juxtaposition such as ab. In elementary arithmetic, multiplication is often understood as repeated addition, a view that generalizes to larger number systems and to algebraic structures.

Key properties describe how multiplication behaves. Commutativity states that a·b = b·a for many number systems, meaning the order of factors does not affect the product. Associativity means (a·b)·c = a·(b·c), allowing regrouping without changing the result. Distributivity over addition holds: a·(b+c) = a·b + a·c, linking multiplication to addition. The multiplicative identity is 1, since a·1 = a, and the zero property states that any number multiplied by 0 equals 0. For integers and real numbers, sign rules apply: (-a)·b = -(a·b) = a·(-b).

Multiplication extends beyond plain numbers to polynomials, vectors, matrices, and complex numbers. Polynomial multiplication combines terms by expanding products; matrix multiplication requires compatible dimensions and is generally not commutative, though it is associative. In programming and computing, multiplication is a binary operator with precedence considerations and potential overflow or floating-point errors to manage.

In Estonian education and usage, korrutusega is taught through the times table (korrutustabel), mental math, and formal algorithms for long multiplication. It also appears in mathematical notation, scientific texts, and everyday calculations where “multiply by” or “times” guidance is needed.