Arithmetic operators

An arithmetic operator is essentially a symbol that performs maths.

They’re usually self-explanatory - the expression 3+4 evaluates to 7 - but you may not be familiar with all of the symbols used in C#!

Addition

You can do addition with the + operator:

int sum = 3 + 4; // 7
double total = 5.5 + 2.3; // 7.8
char letter = (char)('A' + 4); // 'E'

Note that the + operator can also be used to concatenate (join together) strings:

string greeting = "Hello, " + "world!"; // "Hello, world!"

Its purpose depends on the data types of the values being added together.

Subtraction

You can do subtraction with the - operator:

int difference = 10 - 4; // 6
double result = 5.5 - 2.3; // 3.2

Multiplication

You can do multiplication with the * operator (an asterisk, not the times symbol × or letter x):

int product = 3 * 4; // 12
double result = 2.5 * 4.0; // 10.0

Order of operations

When you have multiple arithmetic operators in a single expression, the order of operations matters!

C# follows the normal mathematical order of operations - you probably know this as BIDMAS, BODMAS, PEMDAS, or something similar.

In the expression 3 + 4 * 2, the multiplication is done first, so the result is 3 + 8, which is 11.

You can use parentheses () to change the order of operations. In the expression (3 + 4) * 2, the addition is done first, so the result is 7 * 2, which is 14.