A floating point number is one that has a dot in it, like 0.5 and 10.8. You
don’t need any special syntax to set these types of numbers up. Here’s an example
for you to try:
<?php
$first_number = 1.2;
$second_number = 2.5;
$sum_total = $second_number + $first_number;
print ($sum_total);
?>
You add up, subtract, divide and multiply these numbers in exactly the same
way as the integers you’ve been using. A warning comes with floating point numbers,
though: you shouldn’t trust them, if you’re after a really, really precise answer!
Some Exercises
To round up this section on number variables, here’s a few exercises (In your
print statements, there should be no numbers just variable names):
Exercise
Write a script to add up the following figures: 198, 134, 76. Use a print statement
to output your answer.
Exercise
Write a script to add up the following two numbers: 15, 45. Then subtract the
answer from 100. Use a print statement to output your answer.
Exercise
Use variables to calculate the answer to the following sum:
(200 * 15) / 10
Use a print statement to output your answer.
In the next part of these PHP tutorials, we’ll take a look at Conditional Logic.

Kaynak : https://www.homeandlearn.co.uk/php/php2p10.html ‘sitesinden alıntı