Tricks to Google search you never knew

I know you might think that you are already a pro in searching something in Google because you've been using it for a very very long time. But, 3 out of 4 students can't get their research done as efficient as they should. Even if you're not included, most probably you don't know at least a few of the below points (if not all).

Normal searches

site:example.com
Google will only search the pages of example.com.

"plastic toys"
Quotation marks tells Google to search for both phrases together, not separately  nor just one of them.

-robots
Dash excludes robots from the search results.

2014..2016
This specifies the timerange of the desired search results.

~college
Google would also search for similar words like higher education.

Documents/papers

filetype:pdf
Only PDF results

intitle:maths
It would search for documents that have "maths" in the title. So, it's more helpful for those searching for papers, researches, reports and so on.

*box
The word "box" could be replaced by any common terms in your search along with other results. For example, Black Box.

author:brown
Especially in Google Scholar, this would bring up results that have Brown as the author, not just a word that could be found in the paper.

Others

define:gossip
Google will bring up results that give the definition of Gossip.

(2*4)/3+1 
Google will calculate and give you the answer for simple arithmetic problems without the need to enter any website.

20 pounds in kilograms
Google will convert the units and give you the exact desired answer without the need to enter any website.


Is there any other tricks you know? Let us know in the comments!