There have been a few questions regarding installing this package in the past, but they now seem to be out of date. I'm using MiKTeX 2.9 and TexMaker. When I try \usepackage{mathtools} in TexMaker it will try to install the package for me but will fail. I took the advice given in this thread:
How to install mathtools package?
As suggested I tried installing the mh package using the MiKTeX Package Manager, unfortunately I get the "unknown archive size" error, which I have read means that the package no longer exists. Another thread (lost the link) said you can use the MiKTeX Package Manager to directly install mathtools, however I do not see mathtools listed anywhere in the MiKTeX Package Manager...
So I ask, is the package under a different name? Are there any other ways to install this package?


mhbundle was broken in two:mathtoolsandbreqnwill be maintained separately from now on. – barbara beeton Sep 06 '14 at 20:51