How can you split the coins into two piles such that there are same number of heads up in each pile?

Question

100 coins are lying flat on a table. 10 of them are heads up and 90 are tails up. How can you split the coins into two piles such that there are same number of heads up in each pile?

Answer 1

1. perfect way - Divide10 heads up coins into two piles 5 : 5 and then divide the rest 90 tails up coins at random
   and them 5 :5 heads up coins.

2. another way - Close your eyes and split the coins into two piles 10 : 90 then flip over the 10 coin pile.