Arithmetic Operators

Part of the Fundamentals section of Coddy's PHP journey — lesson 15 of 71.

Now that you know how to work with variables and data types, let's perform calculations with them. PHP provides four basic arithmetic operators that work just like in math:

Operator	Operation	Example
`+`	Addition	`5 + 3` → 8
`-`	Subtraction	`10 - 4` → 6
`*`	Multiplication	`6 * 7` → 42
`/`	Division	`20 / 4` → 5

You can use these operators with numbers directly or with variables:

<?php
$price = 25;
$quantity = 4;
$total = $price * $quantity;
echo $total; // Outputs: 100
?>

You can also combine multiple operations in a single expression:

<?php
$result = 10 + 5 - 3;
echo $result; // Outputs: 12
?>

Challenge

Easy

Read three numbers from input: a price, a quantity, and a discount amount.

Calculate the total cost by multiplying the price by the quantity, then subtract the discount from that result.

Print the final total.

Example:

If the inputs are 50, 3, and 25, the output should be 125 (because 50 × 3 - 25 = 125).

Cheat sheet

PHP provides four basic arithmetic operators:

Operator	Operation	Example
`+`	Addition	`5 + 3` → 8
`-`	Subtraction	`10 - 4` → 6
`*`	Multiplication	`6 * 7` → 42
`/`	Division	`20 / 4` → 5

Use operators with variables:

<?php
$price = 25;
$quantity = 4;
$total = $price * $quantity;
echo $total; // Outputs: 100
?>

Combine multiple operations:

<?php
$result = 10 + 5 - 3;
echo $result; // Outputs: 12
?>

Try it yourself

<?php
// Read input
$price = intval(fgets(STDIN));
$quantity = intval(fgets(STDIN));
$discount = intval(fgets(STDIN));

// TODO: Write your code below to calculate the total cost


// Output the result
echo $total;
?>

Test yourself

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

Arithmetic Operators

Cheat sheet

All lessons in Fundamentals