Arithmetic and assignment operators in C#


Operators are symbols that are used to perform operations on data. The range of different operations you can perform can usually be placed in these four categories:

  • Arithmetic operators
  • Assignment operators
  • Equality operators
  • Logical operators

In this tutorial we will look at arithmetic and assignment operators used in the C# language. Later on in these tutorials we will also look at equality and logical operators when we work with conditional statements.

Arithmetic operators

Arithmetic operators are used for performing standard math operations on variables and are usually only used on number variables eg. int and float (although they can be used for other things too eg. the  + operator can be used to join two strings together).

Operator Name / description
+ Addition – this operator is used to add two numbers together. It can also be used to concatenate (join) two strings together.
Subtraction – this operator is used to subtract one number from another.
* Multiplication – this operator is used to multiply two numbers together.
/ Division – this operator is used to divide one number by another.
% Modulus – this operator is used to divide one number by another but instead of returning the result, it returns the remainder of the division. Eg. 5%2 would return a result of 1.

Brackets can also be used for more complex math operations eg. 5 + (10 * (6 / 3) / 2);

The assignment operators follow standard mathematic order of operations. That means that the math works from left to right. Parenthesis are done first, multiplication and division comes second, and then addition and subtraction come third.

Assignment operators

Assignment operators are used to assign a value to a variable. The most frequently used assignment operator is the equals (=) sign. There are other operators as well that are used to combine multiple operations into one. The syntax of a standard variable assignment looks like this:

<variable name> <assignment operator> <value>;

For example: x = 5; (or int x = 5; if the variable’s type has not already been declared).

The table below shows the different assignment operators available in C#.

Operator Description
= The equals sign is used to assign the value on the right side of the equals sign to the variable on the left side of the equals sign.
+= , -= , *= and /= These assignment operators are also used to perform arithmetic operations and assign the result to the variable eg. x *= 5 is the same as saying x = x * 5.
++ and — These assignment operators are called increment and decrement operators and are used to increase or decrease the value of a variable by 5. For example, x++ is the same as saying x = x + 1.

Watch the video below to see how arithmetic and assignment operators are used in the C# language and then scroll down for the sample code.

Sample code

using System;

namespace MyCSharpProject
  class MainClass
    public static void Main(string[] args)
      string message = "The result is ";
      float num1 = 6f;
      float num2 = 4f;

      float result = num1 + num2 + 10f;

      result = num1 - num2;
      result = num1 * num2;
      result = num1 / num2;
      result = num1 % num2;

      int num3 = 30;


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