Yhteenlasku

Yhteenlasku (addition) is a fundamental arithmetic operation that combines two numbers to produce their sum. For numbers a and b, the result is a + b. The operation is commutative (a + b = b + a) and associative ((a + b) + c = a + (b + c)). The additive identity is 0, since a + 0 = a. Subtraction serves as the inverse operation: a - b = a + (-b).

Yhteenlasku applies to various number systems, including natural numbers, integers, rational numbers, real numbers, and complex numbers. It also extends to vectors and matrices, where addition is performed componentwise (and elementwise for matrices).

In decimal notation, addition is often performed with a column method and carries. It can be executed mentally, with a calculator, or by a computer. Negative numbers are treated by adding their opposites: 7 + (-3) = 4.

In education, yhteenlasku is a foundational skill, taught early and used throughout mathematics, science, finance, and daily life. In computing, addition is implemented at the hardware level as binary addition and forms a core operation in algorithms and data processing.