Maths Riddle

On a table are 20 identical coins.
Six of the coins are showing Heads, the rest Tails.

You are blindfolded.
You cannot tell Heads from Tails by touch.

Separate the coins into 2 sets so that there is the same number of Heads in each set.

website I came across recently

I really enjoyed this website. It gives lot of notes for all chapters required for higher level maths classes. It is helpful both for teachers as well as students.

http://tutorial.math.lamar.edu/

Cheers,
Kalyani

i - complex number vs current notation

I have heard that there is some reason why the letter i , which is a complex number is used to represent the current. Any one knows why?