Multiplication
Multiplication is one of the four operations of elementary arithmetic with addition, subtraction, and division. This operation is often noted with the multiplication cross "×", but can also be denoted by other symbols or by the absence of a symbol. The multiplication of two integers can be seen as a repeated addition several times. For example, "3 times 4" can be seen as the sum of three numbers 4 and "4 times 3" as the sum of 4 numbers 3: 3 times 4 = 4 multiplied by 3 = 4 times 3 = 3 multiplied by 4 = and we write: Multiplication can make it possible to count elements ranked in a rectangle or to calculate the area of a rectangle whose length and width are known. It also allows to determine a purchase price knowing the unit price and the quantity bought. The multiplication is generalized to other sets than the classical numbers. For example, one can multiply complexes between them, functions, matrices and even vectors by numbers.