SpeQ Mathematics - SpeQ is a small, extensive mathematics program with a simple, intuitive interface.
YouTube Kids - YouTube for the youngins on iOS and Android
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
Learney - Knowledge aggregator for developers
NoteCalc - Browser-based notepad built for math calculations.
Cubetto - Cubetto is the friendly wooden robot that will teach your child the basics of computer programming through adventure and hands on play. Montessori approved, LOGO Turtle inspired.