Try running the following at the command line.

To just get the version information:

php -v

Or to get a lot of info:

php -i

It should give you all information you need about the php install.

I use the following command to view installed PHP versions in Ubuntu:

sudo update-alternatives --list php

Second way go to php directory where all PHP version configuration file stored:

cd /etc/php 
dir 

Output:

 > 5.6  7.0  7.1

Do it from your command line:

php -v
mysql -V

and:

php -i | grep -i '^libxml'

OR

Put this in your root directory:

 <?php
    phpinfo();
 php?>

Save it as phpinfo.php and point your browser to it (this could be http://localhost/phpinfo.php)

Extending Jeff Schaller's answer, skip the pipeline altogether and just ask for the internal constant representation:

$ php -r 'echo PHP_VERSION;'
7.1.15

You can extend this pattern to get more, or less, information:

$ php -r 'echo PHP_MAJOR_VERSION;'
7

See the PHP list of pre-defined constants for all available.

The major benefit: it doesn't rely on a defined output format of php -v. Given it's about the same performance as a pipeline solution, then it seems a more robust choice.

If your objective is to test for the version, then you can also use this pattern. For example, this code will exit 0 if PHP >= 7, and 1 otherwise:

php -r 'exit((int)version_compare(PHP_VERSION, "7.0.0", "<"));'

For reference, here are timings for various test cases, ordered fastest first:

$ time for (( i=0; i<1000; i++ )); do php -v | awk '/^PHP [0-9]/ { print $2; }' >/dev/null; done

real    0m13.368s
user    0m8.064s
sys     0m4.036s

$ time for (( i=0; i<1000; i++ )); do php -r 'echo PHP_VERSION;' >/dev/null; done

real    0m13.624s
user    0m8.408s
sys     0m3.836s

$ time for (( i=0; i<1000; i++ )); do php -v | head -1 | cut -f2 -d' ' >/dev/null; done

real    0m13.942s
user    0m8.180s
sys     0m4.160s

First part, what's installed.

This all goes back to package versioning schemes, and why you're getting confused. So, lets dissect it into its individual parts. Assuming it conforms to typical Debian versioning and such, then...

Take php7 you stated:

PHP 7.0.0-2+deb.sury.org~trusty+1

This string is dissected as follows:

• PHP = the software name
• 7.0.0 = the version of that software (from PHP's own versioning schemes)
• -2 = the Package Revision number - that is, how many different packaging changes have been done - this would be the "Second Package" which means they made changes to the packaging or applied patches through quilt in the second version.
• +deb.sury.org indicates the repository source - it's from deb.sury.org repos, which are actually PPAs running on Launchpad, with packages made by the one who runs the deb.sury.org website.
• ~trusty+1 - This indicates additional version specific changes done for the repository - this is an Ubuntu Trusty, package, and likely is either the first or second revision of the package (depending on if they ever had +0 or not) specific for Trusty.

TL;DR: This is a PHP 7.0.0 package, but it has had a couple of revisions since the initial PHP 7.0.0 package.

Second part, how to get PHP 7.0.2.

The repository you are using is a PPA - likely this one.

It was informed to me that 7.0.2 is available and you need to run apt-get update && apt-get upgrade. That should put you on the right versions. If it doesn't, then try using apt-get dist-upgrade as there may be other dependencies that need added and the upgrade was held back because of that.