CsharpHow-ToBeginner · 3 min read

How to Use Arithmetic Operators in C# - Simple Guide

In C#, you use +, -, *, /, and % as arithmetic operators to perform addition, subtraction, multiplication, division, and modulus operations. These operators work with numeric types like int and double to calculate values in expressions.

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Syntax

Arithmetic operators in C# are used between two numeric values or variables to perform calculations. Here are the common operators:

+ : Adds two numbers.
- : Subtracts the right number from the left.
* : Multiplies two numbers.
/ : Divides the left number by the right.
% : Gives the remainder of division (modulus).

Example syntax: result = a + b;

csharp

int a = 10;
int b = 3;
int sum = a + b;       // 13
int diff = a - b;      // 7
int product = a * b;   // 30
int quotient = a / b;  // 3 (integer division)
int remainder = a % b; // 1

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Example

This example shows how to use arithmetic operators with integers and doubles, and prints the results.

csharp

using System;

class Program
{
    static void Main()
    {
        int x = 15;
        int y = 4;

        Console.WriteLine($"x + y = {x + y}");
        Console.WriteLine($"x - y = {x - y}");
        Console.WriteLine($"x * y = {x * y}");
        Console.WriteLine($"x / y = {x / y}");
        Console.WriteLine($"x % y = {x % y}");

        double a = 15.0;
        double b = 4.0;

        Console.WriteLine($"a / b = {a / b}");
    }
}

Output

x + y = 19 x - y = 11 x * y = 60 x / y = 3 x % y = 3 a / b = 3.75

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Common Pitfalls

One common mistake is using integer division when you want a decimal result. Dividing two integers truncates the decimal part.

Also, dividing by zero causes a runtime error.

csharp

int a = 7;
int b = 2;

// Wrong: integer division truncates decimal
int resultWrong = a / b;  // resultWrong is 3

// Right: use double to get decimal result
double resultRight = (double)a / b;  // resultRight is 3.5

// Division by zero example (will cause error)
// int error = a / 0;

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Quick Reference

Operator	Meaning	Example	Result
+	Addition	5 + 3	8
-	Subtraction	5 - 3	2
*	Multiplication	5 * 3	15
/	Division	5 / 3	1 (int), 1.666... (double)
%	Modulus (remainder)	5 % 3	2

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Key Takeaways

Use +, -, *, /, and % to perform basic math operations in C#.

Integer division truncates decimals; cast to double for precise division.

Avoid dividing by zero to prevent runtime errors.

Arithmetic operators work with numeric types like int and double.

Use modulus % to find the remainder after division.