Moved into a new place Oven is questionable, help?

So we moved into a new apartment the oven is OLD. We are trying to bake cookies and the oven has a Dail that says sim .2 .3 .3 .4 .5 .6 hi. So we have no idea what degrees correlate to the numbers. We tried 4 as a middle and the cooks for 8 mins (they are supposed to be done for 10) they started to burn. So we tried the next batch at 3 (and moved the rack up a little high away from the heat) these burnt faster. So we are so lost. Does anyone else have an oven like this? and now what the temps might be? and yes I've tried googling it and keep getting different answers.