Or another easy way to look at it is your long option will automatically be "sold" for you and your short option will be "bought" for you at the settlement price. So if the SPX settled at 1299 in your example, your long 1290 puts would be "sold" for you a zero, as they are out of the money. Your short 1300 puts would be "bought" for you at 1, as they are $1 in the money.
Atticus did answer your question right away, you just have to be able to translate to the language the rest of us speak. I am always amazed at how a simple question on an internet forum can generate so many replies that don't answer the original question. The worst is when someone actually goes to the trouble to post "I don't know".
Arnie, First, yes your question is dumb, but second I like you find it annoying when these people won't answer the question. They should either answer the "stupid" question, or ignore the post. Answer to YOUR question: 1) Assuming SPX options. If you are short 10 contracts of the SPX 1300 and long 10 contracts of the SPX 1290 at expiration, and SPX finishes at 1299 (this is the SOQ for the monthly or final settlement of the weekly series). Your 10 contracts is action on 1000 "shares". Given the settlement value which is posted on the CBOE site, your broker will debit $1,000 against your account for the short contract, and you will get no credit for the long position that has finished out of the money. 2) If you were asking about SPY, then the answer is more difficult. You need to be VERY careful about settlement rules when dealing with physically settled options. There are multiple disasters that could happen, which you should avoid unless you understand the risks. In a nutshell you will be short an in the money put. Thus, someone will exercise the put. Your account will recieve the strike price of the put and you will be long the SPY underlying going into the Monday open. Depending on the size of your account, your broker may take "remedial" measure to prevent this. This measures typically work against you. Too many potential disasters to list, and not your question. Hope that helps.