Xperiment

Change the result by adding after google 
[[google:2*4|Add your computation by clicking on edit]]
[[google:16318199/33883|482/km²]], giving 482/km².
With a suitable browser the evaluated expression pops up, so the link is useful even without following it.
Suppose that someone updates the population figure but not the density, than the next person can see that the density is not based on the latest figure, replace the first number, press Preview, follow the link, copy the new result to the link label, and save. Thus the update requires a minimum of effort. 
Unfortunately, the result 482 has to be entered manually and consistency is not automatically maintained.
==Without putting the result on the page==
Alternatively, the user has to follow the link to see the result. Using template:popd is convenient and there is no redundancy, hence no worry about consistency:
{{popd|16318199|33883}} gives: 
Once we edit Template:Popd. (did so locally ... on this wiki)
hmmmmm ... 
wondering if we can query the user to enter variables via a form?
a wiki calculator using google. ;) -ts-
== Photo Template ==
{{Template:Photo}} gives:
 
see Template:Photo = 
[[Image:Still.jpg|right|thumb|240px|Leaf on brick]]
 
how may this be of use?
use for main page setup ...
edit at the template instead of main page.
is that of use? ;)
== Using a Template and Raw Signature ==
:Created a new template to give this sig: 
:which links to either your own User or User_Talk page.
:The normal way of typing signatures is to type ~~~ or ~~~~ if you want the time and date added at the end. 
:To preserve this while using the Template:UT, go into your Preferences at the top right and put this as the 
:Raw Signature: (inside curly brackets) {{OT|Your User Name}} (and tick the box) 
:Using your own user name: {{UT|Lobster}} or {{UT|Lynnkub}} or {{UT|Steve}} or {{UT|Vcoo}} for example. 
:You should then be able to type just ~~~ or ~~~~ and it will put in the template signature.
:like so: or or or with or without the time sig.
: 00:09, 16 Feb 2005 (GMT)