Tutorial 16: Arithmetic Operators

This is where we start getting into some math! It's very basic, but incredibly useful. Check out this table, provided by PHP.net:

Example	Name	Result
$a + $b	Addition	Sum of $a and $b
$a - $b	Subtraction	Difference of $a and $b
$a * $b	Multiplication	Product of $a and $b
$a / $b	Division	Quotient of $a and $b
$a % $b	Modulus	Remainder of $a divided by $b

The modulus operator is usually a pretty confusing concept at first, but mathforum.org provides a pretty good explanation here:

The "mod" operator in computer languages is simply the remainder. For example,

17 mod 3 = 2

because

17 / 3 = 5 rem 2

which in turn means

17 = 3 * 5 + 2

Here is an example of how you would use one of the above arithmetic operators:

<?php

	$birthYear = 1988;
	$thisYear = date('Y');
	
	$myAge = ($thisYear - 1988);
	
	echo $myAge;

?>

Feel free to experiment with all of the above arithmetic operators with some PHP using the practice.php page provided in this folder.