What's a repeating bar?

When you do a division problem and the quotient (answer) ends up being with a number that just keeps repeating say like when you divide

20 ÷ 9 = 2.22222222222

In this case you don't have to write all these 2s, you just put a line on top of the second 2 after the decimal to show that it repeating.     

     _ 
2.22

That line is a repeating bar.

Hope this helps. :)