Earlier this month, this blog was sponsored by a Mac app called Magic Number, a beautiful calculator application with advanced features. Here’s a quick overview of the extensive feature list.

Dennis Liu, the developer of Magic Number, has offered BrettTerpstra.com readers a chance to win one of 5 free copies ($10 value) of this great app.

Just enter a name and email below (no spam, I promise). Winners will be drawn randomly at 12pm CST on Tuesday, Dec 22. One entry per person.

Sorry, this giveaway has ended.