I'm really new to LaTeX and am having a problem with mathtools.sty. I am using MikTeX and Texmaker.
When I try to create the pdf (compile?) it gives me the error:
! LaTeX Error: File `mathtools.sty' not found.Type X to quit or to proceed,or enter new name. (Default extension: sty)Enter file name:! Emergency stop. \usepackage
I looked this problem up on Google, and found a thread on this place. It said to open the Package Manager and download it there. I opened the Package manager, downloaded mathtools from it by pressing the "+". After doing this it still comes up with the same error, that mathtools.sty is missing.
I have tried reinstalling everything and still nothing works.
I really hope you can help and explain in a simple manner, so that even I can understand :)

+with a right-click to select. I'll change that at once. – Bernard Sep 11 '14 at 12:48mhpackage in two parts (with different maintainers). You should first synchronise MiKTeX Package Manager (menuRepository->Synchronize) to ensure the packages database is up-to-date. Then selectmathtoolsin MPM, right-click on it and ask for installing it. That should be all you have to do – Bernard Oct 18 '14 at 15:32mathtoolsin MPM? – Bernard Oct 18 '14 at 15:52mathtools.sty, and can't be found in the package list. Many people had similar problems on stack exchange. I read loads of posts, now OK. Thanks again! – Chen Stats Yu Oct 18 '14 at 16:13Namesmall window in MPM's tool bar, then clicking on theFilterbutton. – Bernard Oct 18 '14 at 16:43