Arithmetic operators

Learn basic arithmetic with +, -, *, /, % and ** operators.

Arithmetic operators

In PHP, the basic four operations on numbers use arithmetic operators: + for addition, - for subtraction, * for multiplication, / for division. These signs keep the meaning they have in everyday math.

For example, to compute a cafe's daily revenue you would write $revenue = $price * $cups;. The operator takes two values, produces a new one and assigns it to the variable.

Modulo and exponentiation

Two more operators will come in handy. % (modulo) gives the remainder of a division: 17 % 5 returns 2 because 17 = 3*5 + 2. It is great for even/odd checks or minute-to-second conversions.

** raises to a power: 2 ** 3 returns 8. The same as multiplying three 2's together. Use it for areas or compound interest.

Exercise Compute the total price

Declare a $total variable and assign the product of $price and $quantity. Then print $total with echo. Use the * multiplication operator.

Show example solution

To find the total, write $total = $price * $quantity and print it with echo.
Example solution:
<?php
$price = 25;
$quantity = 4;
// Total price
$total = $price * $quantity;
echo $total;

Test yourself

What is the output of echo 6 * 7;?
```
echo 6 * 7;
```
- 36
- 42
- 13
- 67
Show answer

42 — Correct. 6 times 7 is 42.

Write the remainder operator

$remainder = 17 ____ 5;
echo $remainder;

Show answer

$remainder = 17 % 5;
echo $remainder;

Match each operator to its meaning

+

Addition
-

Subtraction
*

Multiplication
/

Division

Next lesson: Assignment operators

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