🔹 1. What Are Operators?

Operators are symbols that tell PHP what action to perform on values or variables. They’re the
verbs of programming — they add, compare, or decide.

There are four main categories:

• Arithmetic Operators
• Assignment Operators
• Comparison Operators
• Logical Operators

🔹 2. Arithmetic Operators

Used for basic math operations.

$x = 10;
$y = 3;

echo $x + $y; // 13
echo $x % $y; // 1

🔹 3. Assignment Operators

These store and update variable values.

🧠 Shortcut tip:

$count = 1;
$count += 4; // $count is now 5

🔹 4. Comparison Operators

Used to compare two values and return true or false.

$a = 10;
$b = "10";

var_dump($a == $b);  // true
var_dump($a === $b); // false (different types)

🔹 5. Logical Operators

Used to combine multiple conditions.

🧠 Use these inside if-statements to control logic.

🔹 6. Increment & Decrement

Used for counting loops and math logic.

$x = 5;
$x++; // 6
$x--; // 5

🧩 7. Operator Precedence

When multiple operators appear in one statement, PHP follows an order of evaluation — similar to math rules.

• Parentheses ()
• Multiplication / Division / Modulus
• Addition / Subtraction
• Comparison
• Logical

$result = 5 + 3 * 2; // 11, not 16

Because multiplication happens before addition.

🧪 Hands-On Practice

Exercise 1: Simple Math

Create a file math.php:

<?php
$a = 10;
$b = 5;

echo "Addition: " . ($a + $b) . "<br>";
echo "Subtraction: " . ($a - $b) . "<br>";
echo "Multiplication: " . ($a * $b) . "<br>";
echo "Division: " . ($a / $b) . "<br>";
echo "Remainder: " . ($a % $b) . "<br>";
?>

✅ Output should show all five arithmetic results.

Exercise 2: Comparison Practice

<?php
$x = 20;
$y = "20";

var_dump($x == $y);
var_dump($x === $y);
var_dump($x != $y);
var_dump($x !== $y);
?>

✅ Observe which ones are true vs false — this demonstrates the difference between value and type.

Exercise 3: Logical Operator Check

<?php
$age = 25;
$has_license = true;

if ($age >= 18 && $has_license) {
    echo "You are allowed to drive.";
} else {
    echo "You are not allowed to drive.";
}
?>

✅ Try changing $has_license to false and reloading the page.

Exercise 4: Increment Challenge

<?php
$count = 1;
while ($count <= 5) {
    echo "Count is: $count <br>";
    $count++;
}
?>

✅ Outputs 1 to 5. 💡 Replace ++ with += 2 to count by twos!

🧮 Mini Project – Discount Calculator

Goal: Build a script that calculates a final price after applying a percentage discount.

Create a file called discount.php:

<?php
$price = 100;
$discount = 15; // in percent

$final_price = $price - ($price * ($discount / 100));

echo "Original Price: $$price <br>";
echo "Discount: $discount% <br>";
echo "Final Price: $$final_price";
?>

✅ Output:

Original Price: $100
Discount: 15%
Final Price: $85

🧾 Module 3 Quiz

💪 Challenge Task – Simple Grade Calculator

Objective: Combine operators, comparisons, and logic to build a grade evaluator.

1. Create a file named grade.php.
2. Ask for a student’s score (assign manually for now):

$score = 87;

3. Use conditional statements to determine the letter grade:

<?php
$score = 87;

if ($score >= 90) {
    $grade = "A";
} elseif ($score >= 80) {
    $grade = "B";
} elseif ($score >= 70) {
    $grade = "C";
} elseif ($score >= 60) {
    $grade = "D";
} else {
    $grade = "F";
}

echo "Score: $score<br>Grade: $grade";
?>

✅ Test multiple values for $score and confirm the logic works.

🧾 Submission Checklist

• ✅ math.php → arithmetic demo
• ✅ discount.php → correct final price calculation
• ✅ grade.php → grade output with logic
• ✅ Quiz answers filled out

🏁 Next Step: In Module 4, you’ll take these skills and learn to control the flow of your programs —
using if statements, loops, and switch cases to make PHP truly interactive.