Arithmetic Operators

Part of the Fundamentals section of Coddy's Swift journey — lesson 16 of 86.

Swift provides arithmetic operators to perform basic mathematical calculations. These work just like the math you already know, making it easy to add, subtract, multiply, and divide numbers in your code.

Here are the four basic arithmetic operators:

let sum = 10 + 5        // Addition: 15
let difference = 10 - 5 // Subtraction: 5
let product = 10 * 5    // Multiplication: 50
let quotient = 10 / 5   // Division: 2

When dividing integers, Swift performs integer division — it discards any decimal portion and returns only the whole number. If you need decimal results, use Double values instead:

let intResult = 7 / 2       // 3 (integer division)
let doubleResult = 7.0 / 2.0 // 3.5 (decimal division)

You can combine multiple operators in a single expression. Swift follows standard mathematical order of operations — multiplication and division happen before addition and subtraction:

let result = 2 + 3 * 4  // 14, not 20
let grouped = (2 + 3) * 4 // 20 (parentheses first)

Challenge

Easy

Write a function calculateExpression that takes three integers a, b, and c, and returns the result of the expression: a + b * c.

Remember that Swift follows standard mathematical order of operations — multiplication happens before addition.

Parameters:

a (Int): The first number
b (Int): The second number
c (Int): The third number

Returns: The result of a + b * c (Int)

Cheat sheet

Swift provides arithmetic operators for basic mathematical calculations:

let sum = 10 + 5        // Addition: 15
let difference = 10 - 5 // Subtraction: 5
let product = 10 * 5    // Multiplication: 50
let quotient = 10 / 5   // Division: 2

Integer division discards decimals and returns only whole numbers. For decimal results, use Double:

let intResult = 7 / 2       // 3 (integer division)
let doubleResult = 7.0 / 2.0 // 3.5 (decimal division)

Swift follows standard order of operations (multiplication and division before addition and subtraction). Use parentheses to change the order:

let result = 2 + 3 * 4    // 14
let grouped = (2 + 3) * 4 // 20

Try it yourself

func calculateExpression(a: Int, b: Int, c: Int) -> Int {
    // Write code here
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments

4Operators Part 1

Arithmetic OperatorsModulo Operator Compound Assignment Recap - Simple Math Comparison Operators

7Basic IO

Print Function String Interpolation ReadLine Input Type Conversion Recap - Till 120 Recap - True or False

10Functions

Declare A Function Parameters And Arguments Return Values Argument Labels Recap - Sigma Function Recap - Validation Function Default Values

13Iterating Over Sequences

Iterating Over Elements The Enumerated Method Iterating Over Strings P1 Iterating Over Strings P2

16Final Challenges

Flat Asterisk Pyramid Pattern Finder What To Buy

2Variables

Let vs Var Type Annotations Numbers String Boolean Naming Conventions Recap - Initialize Variables

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Ternary Operator

8Bill Split Calculator

Welcome Message Getting Input

Calculating Tip And Total

Splitting The Bill

Formatted Output

11FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

14Arrays Advanced

Array Slicing Part 1 Array Slicing Part 2 Sequence Operators The Contains Method