Mac: Previously mentioned calculator superstar Numi is on sale today for just $0.99. It combines standard calculations with text in plain English to work out complex maths in a simple, easy way.
Numi normally costs anywhere from $5 to $10, but it's available today for just $0.99. We've always liked the clever app but felt it cost a bit much. Now's your chance to pick it up for a lot less.
Numi ($0.99) [Mac App Store]