vCalc is a keyboard driven scientific calcualtor,
that works using the RPN notation common in well
known scientific calculators. It supports a complete set of math, binary
and statistical operations.

Barres is a simple barcode generation application for Macintoshes. It can generate the following type of barcodes: UPC (12 digits), EAN13 (13 digits), and SCC14 (14 digits). By extension of the EAN code, the JAN13 and ISBN-EAN formats can be created

Julius is a simple converter for the translation of numbers written with arabic digits into roman digits, and it is able to translate roman numbers in arabic ones.
The use of Julius if very easy: First choose the direction with the tabs, then simply write (or paste) the number (under 4000, and strictly positive with no decimal if typed in arabic), click on the convert button, and the converted number is displayed, in a copy-enabled field.