The 0.1 version of Scira for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Scira for Mac lies within Education Tools, more precisely General. We recommend checking the downloaded files with any free antivirus. The actual developer of this free software for Mac is Steven Carlson.
From the developer:
Scira is a simple calculator that performs base conversion and simple math on numbers with the same or dissimilar bases.
You may want to check out more Mac applications, such as JXCirrus Maths, which might be related to Scira.