Math Operators in GDScript

What Is an Operator?

An operator is a symbol that tells the computer to do something with two values, usually numbers. You already know these symbols from math class. Today we’ll use them inside GDScript.

The Four Basic Operators

Symbol	Name	What It Does	Example
+	Addition	Adds two numbers together	5 + 3 = 8
-	Subtraction	Subtracts one number from another	10 - 4 = 6
*	Multiplication	Multiplies two numbers together	6 * 2 = 12
/	Division	Divides one number by another	20 / 5 = 4

Using Operators With Variables

Variables store numbers. Operators let us change what’s stored inside them. Here’s the pattern:

var health = 100
health = health - 15
print(health)   # prints 85

Read the second line as: “take whatever is currently in health, subtract 15, and store the result back into health.” The = sign means “store this value”, it does NOT mean “equals” the way it does in math class.

Shortcut Operators

Because “take a variable, do math, and store it back into itself” is so common, GDScript gives us a shortcut:

Shortcut	What It Does	Same As
+=	Adds and stores	health = health + 10
-=	Subtracts and stores	health = health - 10
*=	Multiplies and stores	score = score * 2
/=	Divides and stores	score = score / 2

Example using the shortcut:

var health = 100
health -= 15
print(health)   # prints 85, same result as before, shorter to write

Order Matters

The computer follows the same order-of-operations rules you learned in math class: multiplication and division happen before addition and subtraction, unless you use parentheses.

var total = 2 + 3 * 4
print(total)   # prints 14, NOT 20

var total2 = (2 + 3) * 4
print(total2)  # prints 20, parentheses go first

Bonus: The Modulo Operator (%)

% gives you the remainder after division. We won’t need it much yet, but it’s useful later for things like “every 3rd enemy drops a coin.”

print(10 % 3)   # prints 1  (10 divided by 3 is 3 remainder 1)