I have a 2010 focus

Press in the black button next to the display to cycle through odometer, trip A, or trip B.

and make sure you are not in metric mode

If you mean that the miles are wrong in the way that it shows too much or too little miles for the amount of gas in the tank, then when you removed the battery it reset the calculation it made and will come right by itself after the second or so tank of gas that you refill.

That's exactly what I meant but I filled It up twice and It's telling me 428 miles per full tank and I know that's not right

Try resetting your average speed and fuel consumption and maybe drive a little "spiritedly" and have a look at what it tells you then? Perhaps you have an optimistic ford on your hands... :-)

I have a 2010 Ford focus how do I reset the milege

How do I get it to show in miles instead of kms..??? What the miles r left in tank instead of kms