What is the best way to teach kindergarteners subtraction?

I have reached the topic of subtraction with my class of kindergartens and I would like some advice on teaching them the concept of subtraction. They currently know that subtraction means to take away, and they can perform basic subtraction problems using blocks, but I would now like to put written problems on the board for them and I would like some tips on how to do that so that I would not confuse them. Can anyone help?