Disclaimer: I do not own Hitchhikers Guide to the Galaxy or Doctor WHo.

AN: This is just a random story that came to me a a result of plot!daleks invading my home. Also there aren't enough of these crossovers. I hope you like it.

The Doctor was working away in the TARDIS, busily rewiring old wires and messing things that, in Martha's opinion, looked like a bunch of random baubles.

"Umm, Doctor, what are you doing?" she asked while jumping back to avoid sparks that had suddenly flew up.

"Well, you see the TARDIS's compacted Bistromatic Drive fried out, something about those folloping Mattresses that it didn't like, and all of these nonabsolute numbers need calculating and separated from the happy numbers. Remember the happy numbers? I explained them when we were about to crash into that sun. And, "

"Whoa Doctor, slow down," Martha said, trying to get her head wrapped around the Doctor had just said, "what the heck is a Bistromatic Drive?"

The Doctor gave Martha that look that said, 'I keep forgetting you aren't as smart as me,' and then said,"Bistromatic Drives are wonderful. Perfect for interstellar travel, and beyond with a few of my own tweaks. You've studies Einstein haven't you? The part about where he said space wasn't absolute, it all depends on your movement in space? Now we've seen time is like that too, it all depends on your movement in time. Now numbers, numbers aren't absolute either, it all depends on your movement in restaurants."

"Sorry, but did you say restaurants?"

"Well yea, restaurants are full of nonabsolute numbers! The exact number is, of course, nonabsolute. Like the number of people the table is reserved for. That will change after the first three telephone calls, then have no resemblance at all to who actually shows up, or who comes after everything is over, or who leave when they see who else arrived."

Martha just stared blankly; the Doctor took this a good sign and continued.

"Oh, and then there is the time of arrival. I love the time of arrival, one of my favorites! It's one of those bizarre mathematics, it recipriversexcluson."

"Sorry, it's what? Recipri-pri,

"Recipriversexcluson, meaning that the number can only be defined as anything but itself, now that's a number with a personality disorder," the Doctor chuckled. "Now one of the most mysterious sets of nonabsolute numbers is,"

"Ok stop!" Martha interrupted, "Enough with the restaurant numbers that may or may not be recipriversexcluson. Honestly Doctor."

"Aww, Martha. I haven't even gotten to the check pad yet. With the numbers of the items on the check to the amount people are prepared to pay. Not to mention who actually brought money."

"I think I get it doctor, or rather I think that it is too impossible for me to possibly get."

"And just imagine, all of this is simply for space travel, I haven't even breached the mathematics behind time travel yet. Now those are some awful numbers. Anyway to put it in simpler terms, all of the calculations for a spaceship can be done on a waiters check pad." The Doctor looked at Martha expectantly.

"'A waiter's check pad? Really? I can't believe it. I was a waiter once; I should have gotten paid more."

"And now you are travelling through time and space, imagine that. On a waiters check pad reality and unreality collide on a fundamental level so that each becomes the other and truly anything is possible, at least within certain parameters."

"What parameters?"

"It's impossible to say, that's one of them,"

"But if one of the parameters is that it's impossible to say what the parameters are, didn't you just say a parameter?"

"Of course not Martha, that's absurd."

It was at this point that Martha gave up trying to understand, and proceeded to walk away leaving the Doctor to his numbers, and hoping that he actually knew what he was talking about. Later the Doctor parked the TARDIS in a nice little bistro in London, ordered a coffee and crumpets, and then proceeded to slip the waiter's check pad away when she wasn't looking. After installing the new check pad the TARDIS was as good as new, she just needed a quick recharge under a certain rift in Cardiff.

So, what did you think? Please review!