Formula to calculate daily quotas

I'm a self-learning, fairly newbie to Excel and need some help with this formula. I have a project going whereby my team members need to make 10 outgoing phone calls per day. At the end of the day, I will input the actual amount of calls they made into the spreadsheet and would like the next cell to calculate plus/minus from that daily quota and keep a running count over the next 60 days. The sheet will look like this:

Cell A2 thru A60 is the Date
Cell B2 thru B60 is the Daily Quota of 10
Cell C2 thru C60 is the Calls Made (let's put 17 in C2)
Cell D2 thru D60 is Plus/Minus Quota

What is the formula to enter into D2 and can I simply drag that formula down to D60?

Thank you in advance for any help someone can provide!

Thank you for your answer. Yes, the dates are sequential down the rows. The =C2-B2 is good for putting that day's results into D2 but how do I keep a "running" total of how much the person is plus/minus
in relation to quota? For example, the daily quota is 10 calls, the person makes 17 calls the first day but only 8 the next day, how can I make D2 show that the person is plus 5 in relation to the 10 per
day quota?
I believe I attached my sheet to this reply but am not sure....

Sorry for the confusion on my part. I want D2 to show the overall +/- and then I want D3, D4 etc...to show that same overall +/- as I add each day's Call Made to the C rows. so in my previous example, with a daily quota of 10 calls:
on day one, the person makes 17 calls: D2 would show (positive) 7
on day two, the person makes 8 calls: D3 would show (positive) 5

That is it EXACTLY...Thank you so much!!!! And my apologies on not explaining in enough detail initially.

Is there a button for that?