Number Drill is my first commercial product. For reasons to buy it (other than to support my open source work, of course) visit the website.
When I was a kid my parents bought a program (which I will refer to as Foo Math) for me and my siblings to practice math on. It was a simple program where you enter math facts as quickly as you could to win a race.
But Foo Math had one big problem for our family; it was self-competitive. Normally I find competing against myself in a game to be fun, but I didn't in Foo Math. I'm not really sure why, perhaps combining it with doing math just didn't mix well.
Move forward 8 years to April 2009 and I still had a few younger siblings that could benefit from Foo Math. But they found it frustrating and stressful. Generally not a recipe for fun. It even made one of my younger sisters cry.
I did some checking around on the internet and found out that we weren't a single case scenario. I decided to create a product to compete with Foo Math, which was aging quite a bit.
So on April 8th I sent off an email to Timberdoodle, a home-school distributor my family had ordered from quite a bit in the past, presenting to them the idea of Number Drill. They showed interest and by the 17th I sent them a prototype.
After a bit of discussion I set to work on creating Number Drill 1.0. I completed it three months later on July 2nd. Or rather, I thought I had completed it.
They liked it but had one major concern; it didn't cover everything that Foo Math did. In fact, Number Drill 1.0 only covered a small subset of the topics. I had all the important topics that would be used 90% of the time, but Timberdoodle knew their customer base better than I did.
It turns out Foo Math had a high price tag for a reason. They had a lot of topics. I spent the next nine days entering sections, topics and races. I reorganized everything. I had to extend my question parser and display module considerably to support fractions, roman numerals and much more. By the end of the nine days the number of solvable problems in Number Drill had gone from a few thousand to over 135,000. Version 1.1 was ready.
I spent the next month building the website, ordering CDs and getting ready to sell. On August 31st I made my first two sales though the website and on September 29th, 2009 I fulfilled Timberdoodle's first order.