Calculating a date interval with epoch timestamps

 
<?php
$birthday = 163727100;
$gestation = 36 * 7 * 86400; // 36 weeks
$whoopee_made = $birthday - $gestation;
?>

1.	Adding two integers together
2.	++$answer and $answer++
3.	Assign an integer value this way
4.	Integer calculation
5.	Integer values can be signed and unsigned in the range from –2,147,483,648 to 2,147,483,647.
6.	Integers can be specified using any of the following syntaxes
7.	Storing Integers in PHP
8.	Using typecasting to convert numbers to strings
9.	To specify a number in hexadecimal, precede it with 0x.
10.	Addendum: finding the largest integer
11.	Int value overflow
12.	Integer value compare with equal sign
13.	Calculating Discount
14.	Divide the two values and print the result
15.	Subtract the two values and print the result
16.	Multiply the two values and print the result
17.	Add the two integer values and print the result.
18.	Subtracted an Integer value
19.	Add an Integer value
20.	Add a PHP block and create a variable that holds an integer

Calculating a date interval with epoch timestamps : Integer « Data Type « PHP