Esperanto the most useful language to learn if you want to proceed to other languages?; EasyMath?

Esperanto may be the most useful language to learn if you want to learn other languages.

http://en.wikipedia.org/wiki/Propedeutic_value_of_Esperanto


I wonder if, analogously, there exists an "easy math". After being comfortable with EasyMath, most kids would have a much easier time learning other math.
Is "logic" an EasyMath? are some video games?

Too much knowledge can be bad for some types of memory

Too much knowledge can be bad for some types of memory, study finds

compare with Beginner's Mind