Write a simple PHP snippet:

1. Open a PHP tag (`<?php`).
2. Use `echo` to print "Hello World".
3. Add a single-line comment explaining the code.

<?php
// Print a welcome message
echo "Hello World";
?>

Define the following variables:

1. `$name` with your name (string).
2. `$age` with your age (integer).
3. `$price` with a price (float 10.5).
4. Print: "My name is [name] and I am [age]".

<?php
$name = "Ahmed";
$age = 25;
$price = 10.5;

echo "My name is $name and I am $age";
?>

Perform the following operations:

1. Define `$x = 10` and `$y = 4`.
2. Print the sum.
3. Print the division result.
4. Print the modulus (remainder).

<?php
$x = 10;
$y = 4;

echo $x + $y; // 14
echo "<br>";
echo $x / $y; // 2.5
echo "<br>";
echo $x % $y; // 2
?>

Work with the string `$text = "Hello PHP"`:

1. Print the string length (strlen).
2. Print the word count (str_word_count).
3. Reverse the string (strrev).
4. Replace "PHP" with "World" (str_replace).

<?php
$text = "Hello PHP";

echo strlen($text); // 9
echo str_word_count($text); // 2
echo strrev($text); // PHP olleH
echo str_replace("PHP", "World", $text); // Hello World
?>

Use constants:

1. Define `SITE_NAME` as "My Website" using `define`.
2. Define `TAX_RATE` as 0.15 using `const`.
3. Print both values.

<?php
define("SITE_NAME", "My Website");
const TAX_RATE = 0.15;

echo SITE_NAME;
echo TAX_RATE;
?>

Check data types:

1. Define `$isActive = true`.
2. Define `$scores = [10, 20]`.
3. Define `$nothing = null`.
4. Use `var_dump()` to print the type and value of each.

<?php
$isActive = true;
$scores = [10, 20];
$nothing = null;

var_dump($isActive);
var_dump($scores);
var_dump($nothing);
?>

Evaluate the following conditions (print the result):

1. Is 10 greater than 5 AND 5 less than 2?
2. Is 10 equal to 10 OR 5 equal to 0?
3. What is NOT true?

<?php
var_dump(10 > 5 && 5 < 2); // bool(false)
var_dump(10 == 10 || 5 == 0); // bool(true)
var_dump(!true); // bool(false)
?>

Manipulate a variable:

1. Define `$count = 10`.
2. Increment it by 1 (`++`).
3. Decrement it by 1 (`--`).
4. Add 5 using `+=`.

<?php
$count = 10;
$count++; // 11
$count--; // 10
$count += 5; // 15

echo $count;
?>

Use built-in math functions:

1. Absolute value of -5 (abs).
2. Square root of 64 (sqrt).
3. Round 3.7 (round).
4. Generate a random number between 1 and 100 (rand).

<?php
echo abs(-5); // 5
echo sqrt(64); // 8
echo round(3.7); // 4
echo rand(1, 100);
?>

Write code that mixes both:

1. Define `$color = "red"`.
2. Print an `<h1>` containing "Hello".
3. Set the text color using the `$color` variable (inline style).

<?php
$color = "red";
?>

<h1 style="color: <?php echo $color; ?>">Hello</h1>