Arithmetic and Precedence
Operators and order of evaluation.
Arithmetic and Precedence is a free C# Academy lesson on CoddyKit. This is lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C# Academy learning path, and your progress syncs across the web and the CoddyKit app. The C# Academy course includes 4 lessons in total.
Arithmetic Operators
C# provides the familiar arithmetic operators:
+addition-subtraction*multiplication/division%remainder (modulo)
They work on every numeric type.
int a = 10, b = 3;
Console.WriteLine(a + b);
Console.WriteLine(a - b);
Console.WriteLine(a * b);Integer Division
When both operands are integers, / performs integer division and discards the fractional part.
So 7 / 2 is 3, not 3.5. This is a common source of beginner bugs.
int result = 7 / 2;
Console.WriteLine(result);Getting a Decimal Result
To keep the fraction, make at least one operand a floating-point or decimal value.
You can add .0 to a literal or cast a variable to double.
double result = 7.0 / 2;
double other = (double)7 / 2;
Console.WriteLine(result);
Console.WriteLine(other);The Modulo Operator
The % operator returns the remainder of a division.
It is handy for checking even or odd numbers, wrapping around ranges, or grouping items.
Console.WriteLine(10 % 3);
Console.WriteLine(8 % 2);
bool isEven = 8 % 2 == 0;
Console.WriteLine(isEven);Operator Precedence
Operators follow a precedence order, just like in math. Multiplication, division, and modulo bind tighter than addition and subtraction.
So 2 + 3 * 4 equals 14, because 3 * 4 runs first.
Console.WriteLine(2 + 3 * 4);
Console.WriteLine(20 - 6 / 2);Parentheses Override Precedence
Use parentheses to force a different order of evaluation. Anything inside them is computed first.
Parentheses also make your intent clearer, even when they are not strictly required.
Console.WriteLine((2 + 3) * 4);
Console.WriteLine(10 - (2 + 3));Left-to-Right Evaluation
When operators share the same precedence, C# evaluates them left to right.
So 10 - 4 - 2 means (10 - 4) - 2, which is 4.
Console.WriteLine(10 - 4 - 2);
Console.WriteLine(24 / 4 / 2);Unary Operators
The unary minus - negates a value, and unary plus + leaves it unchanged.
Unary operators have very high precedence, applying before binary arithmetic.
int x = 5;
Console.WriteLine(-x);
Console.WriteLine(-x + 3);Increment and Decrement
++ adds one and -- subtracts one. Placed before a variable (prefix) the change happens first; placed after (postfix) the original value is used first.
int i = 5;
Console.WriteLine(i++);
Console.WriteLine(i);
Console.WriteLine(++i);Compound Assignment
Compound operators combine arithmetic with assignment: +=, -=, *=, /=, and %=.
So total += 5 is shorthand for total = total + 5.
int total = 10;
total += 5;
total *= 2;
Console.WriteLine(total);Putting It Together
Real formulas combine several operators. Knowing precedence lets you predict the result without testing it.
Below, multiplication runs before addition, and the cast turns integer division into a decimal average.
int sum = 20 + 30 + 25;
double average = (double)sum / 3;
Console.WriteLine(average);Quick Check
Apply what you learned about precedence.
Recap
You practiced the arithmetic operators + - * / %, saw how integer division truncates, and learned to get decimal results with casting.
You also learned operator precedence: * / % before + -, left-to-right for equal precedence, and parentheses to take control. Compound operators like += keep code concise.
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Frequently Asked Questions
Is the “Arithmetic and Precedence” lesson free?
Yes — the full text of “Arithmetic and Precedence” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C# Academy course, upgrade to CoddyKit PRO. The C# Academy course includes 4 lessons in total.
What will I learn in “Arithmetic and Precedence”?
Operators and order of evaluation. You practise C# Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start C# Academy?
No prior experience is required. C# Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 4.
How long does the “Arithmetic and Precedence” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this C# Academy lesson?
Yes. Every C# Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Numeric Types
- Arithmetic and Precedence
- The Math Class
- Converting Between Numbers