I have here a list of some of the most valuable free/open-source educational software for kids. I hope this will in some way serve as a guide to those who want to teach their child at home without the need for spending some extra money.

Tux Paint
Tux Paint is a free, award-winning drawing program for children ages 3 to 12 (for example, preschool and K-6 in the US, key stages 1 & 2 in the UK). It combines an easy-to-use interface, fun sound effects, and an encouraging cartoon mascot who guides children as they use the program.

Kids are presented with a blank canvas and a variety of drawing tools to help them be creative.

Canorus
Canorus is a free music score editor. It supports note writing, scripting support, import/export of various file formats, MIDI input and output and more! Note that Canorus is still in early stage of development and not nearly all the features are implemented yet!

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