Not sure if it&#x27;s suitable for children 3 year old (mine are older already), but CS Unplugged, <a href="http:&#x2F;&#x2F;csunplugged.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;csunplugged.org&#x2F;</a>, is an inspiring collection of free (!) learning activities teaching Computer Science topics through games and puzzles using cards, strings and pencils and some paper. CS concepts like binary number representation, different types of algorithms, data compression and error detection are taught without programming code or the use of a computer.<p>There&#x27;s a nice write up on this in an article in the Communications of the ACM: <a href="http:&#x2F;&#x2F;cacm.acm.org&#x2F;magazines&#x2F;2015&#x2F;3&#x2F;183598-reaching-a-broader-population-of-students-through-unplugged-activities&#x2F;abstract" rel="nofollow">http:&#x2F;&#x2F;cacm.acm.org&#x2F;magazines&#x2F;2015&#x2F;3&#x2F;183598-reaching-a-broad...</a>.