Quick Answer

Handle arithmetic overflow.

Understanding the Issue

This exception occurs when an arithmetic operation exceeds the range of the data type.

The Problem

This code demonstrates the issue:

Csharp Error 
int max = int.MaxValue;
int overflow = max + 1; // Throws in checked context

The Solution

Here's the corrected code:

Csharp Fixed 
// Use checked/unchecked
unchecked {
    int overflow = max + 1; // Wraps around
}

// Overflow checking methods
try {
    int result = checked(max + 1);
} catch (OverflowException) {
    // Handle overflow
}

// Larger data types
long bigNumber = (long)max + 1;

// Math.Clamp (C# 9+)
int safeAdd = Math.Clamp(max + 1, int.MinValue, int.MaxValue);

Key Takeaways

Use checked arithmetic for critical operations and larger types when needed.