Here is a simple piece of software I wrote to help my children practice basic arithmetic facts. Of course there are no doubt already a thousand or more similar programs out there; but in a few minutes of searching I didn’t find one that did quite what I wanted. I ended up tinkering with this for several hours, and even wrote documentation and made an installer. Free download and screenshot below.
I’ve also published the source code over on Github: http://github.com/kylecordes/mathdrill/tree/master
This software is written in Delphi, and though there is some chance that I am the only developer anywhere using both Delphi and git, hopefully this will be wrong, and someone will fork and offer their improvements.