Most rules try to use only addition and subtraction.
Is multiplication (and to an extent division) too complicated to use in live game rules?

I think Shadowrun should move to a variable target number system...

Depends on what and why.

I don't have any troubles with multiplying an attribute or skill by 2 but dividing by 2,43*log(28) is a bit more complicated.
Dividing is okay as long as explicitely written if it's rounded up or down and if it doesn't lead to mass minmaxing.

But multplication and division also have to be really useful. If the rule can be as good while avoiding them, it's just as fine.

Examples include:

Allies cost increasing exponentially with force
AP modifiers that add armor rating (like -2/+Impact)

Multiplying and dividing are okay, as long as they are with small numbers. A multiplier or divisor higher than 3 or 4 is getting too big (with an exception made for powers of 10, perhaps). The same goes for summing sequences of numbers too, anything more that 3 or 4 terms is getting to be too much math.

I'd be willing to make some exceptions for things that are done rarely, or can be calculated in downtime.

I'm with Mal-2 on multiplication, can be OK if it is very simple. In some cases it is arguably better than addition/subtraction if the alternative uses much larger numbers.

However division has another problem, that of rounding off. All the divide by 2s, although not particularly slow by themselves, all have their own rules about which way to round off. :/

So that means I find myself with no option to choose on this poll.....

The rounding is definately a problem. This should always be the same. Not one exception.

In Classic Deadlands, integer division of two digit numbers by 6 and 7 was part of the basic combat mechanic. It seemed like it would be really obnoxious when you first see it, but since everyone quickly realizes that it's just an application of the times tables they memorized in primary school it ends up working fine.

you should go with the simplest operation that will still convey the level of realism you desire. if multiplication is realistic but addition will get you pretty realistic, go with addition. division should generally be avoided unless, as in Deadlands, you're frequently dividing by or into the same number; or if you're talking about relatively simple division (halves, thirds, occasionally even quarters).

if you're going more complex than multiplication and division, that's fine too--just provide tables.

Most of the people I play with have taken Differential Equations...

addition and subtraction should be removed.

If they can´t do numbers I don´t want to play with them. `Nuff said.

That might have been a reply to my smart-ass remark.

It's not so bad, actually - once everyone got into the habit of watching everyone else's dice rolls.

Of course, I could do without hearing yet another reference to the holy-hand-grenade skit ever again.

Multiplication is easy. Division is bullshit.

Sorry, it's true. It's not that division is impossible, or even hard. It's that if you have five people divide small numbers by each other at the same time you'll get two or three answers. It takes a moment to reconcile everything, and that slows play down.

It shouldn't, but it does. Everyone can get the right answer multiplying 5 by 3. But people make a distressing amount of minor errors dividing 15 by 5.

Idon't know why this is, but it happens often enough that I've noticed it in many different groups.

-Frank

All math should be avoided.

After talking with a few Forgites, I've come to the conclusion that for many people, they play despite the system. This holds true for just about every game. The faster you can get to game play, the better off you are, and math is a slowdown. You can add realism through roleplay. (Incidentally, I also play with math dyslexics, so I have a lot of passion for this sort of thing.)

That being said, multiplication and division by 2, 5, and 10 is simple and quick for just about everyone. In fact, it's frequently faster to divide by ten than it is to add 2. My gaming group has been playing 7th sea, which is basically an addition system; but when the numbers start getting big, the counting and adding is slower than a "Multiply by 5" system.

Division by natural numbers is fine. But all kids hate dividing, even if they can handle it with some external motivation. Division is fine if the result is rounded up or down and done by a whole number.

So long as I know the rules for rounding and don't have to go beyond two decimal places, I can generally do division of whole numbers in my head. Simplifying combat math for the sake of speed is fine, but some things need to be complex. Try 3g3 or VDS by BTRC.

Kids today use calculators for everything in a school system designed to hold smart kids back so that dumb people don't need therapy when they grow up. It's bad enough they enter the workforce semi-literate, but now they're dumbing down the RPGs?

There are two ways to handle this. 1) Round down so that the STR 1 character does 0 damage or 2) allow fractional damage

Dividing only reduces granularity due to rounding. No rounding means no loss in granularity.


I'm going to disagree that simple operations are the best choice. Sometimes, simple operations just make things more complicated. Case in point: Vehicle acceleration rules in 3rd and in 4th.

In 4th acceleration is the "running speed" of your vehicle, apparently. It is counterintuitive. In 3rd it was a multiplier applied to a driving test, meaning that you could get 2g acceleration in a crop-duster if the pilot has enough skill.
Are either of these solution really any more elegant that the classic (Integral)a(dt), also known as at+c? No.

Now, I won't go overboard with this, certainly mage should not be taking natural logs to determine drain, that's just perverse. However, some simple "advanced" math could really increase realism and granularity and make the system both faster and easier to grasp.

Personally if I can't do it in my head then it is too complex for game play. Downtime stuff can be a bit more number intensive but if it slows down the game then it is not very elegant.

hyzmarca, my point was that the system could have been designed to avoid these cases without the need to keep track of half DVs. Anyways, it's not the end of the world, but it certainly is a very real (if unimportant) problem of division.

And I can do calculus when I have to - hell! I use it all the time in my studies -, but I'm sure it's possible to come up with decent vehicle rules that don't require any if we try a bit. (I haven't looked much into vehicle movement in SR4, so I don't know how good or bad they are. I was just using your example.)

My point is that many of the people who complain about he math need a calculator (or at least their fingers) to solve x=2+2 and I'm afraid that there is never a happy medium between keeping it real, keeping it playable, and making it accessible to... the mathematically challenged.

I prefer to avoid calculus obviously, but if the dyslexic guy in my group can figure it out in his head then the math is obviously simple. I think the balancing point for complexity is where he can do it with a calculator but I can still do it in my head. Of course, if you can make it playably granular and flexible at a lower level of complexity then by all means do so.

Vehicle design is one of those areas where one has to get complex though; otherwise, you're just pulling numbers out of your dog's rectum. IRL, speed varies with power in an exponential manner while acceleration declines as speed increases due to aerodynamic drag. A little much to calculate in-game, but off-camera when you're trying to hop-up your ride, it helps to know if it's even possible and how much it'll cost and when you start hitting the point of diminishing returns inherent in the 'cubic dollar' theory of racing. This if where rolled my eyes at SR's previous attempts at a vehicle design system.

Games are a bad place to LEARN math (or economics) from. I began learning about probability from gaming, too, only to later learn from talking with Math majors that everything I thought I knew about probability was way off.

I can't, really. Once I learn something, I'm incapable of remembering what it was like not to know it, nor do I remember the specifics of how I was wrong.

Plus I'm still not sure enough of my grasp of math to really try explaining anything over the interweb. I don't actually do anything besides gaming that requires more than a rudimentary knowledge of arithmatic, so I'm Uber rusty. I'd be horribly embarrassed if I got some basic thing wrong.

Suffice it to say that the statistical analysis I was using for gaming was missing a few important factors, because they were common sense based. The math major taught me some actual rules for statistics. So, learn from math classes first, THEN apply to gaming. Not the other way around.

We use bad probability all of the time. 3 dice will probably give 1 hit at TN 5, for example.

That's inaccurate because it is oversimplified.

In reality, 1 die has a 1/3 chance of 1 or more hits, 2 dice has a 5/9 chance of 1 or more hits, and 3 dice have a 19/27 chance of 1 or more hits

Personally, I good at math.

I've always been a fan of formulae myself instead of tables. When I see tables, I try and make a formula out of it for easy reference. Once I have the formula, I can make my own tables!

Biggest place this is handy to have a formula is with explosives DV calculation and blast radius.

Complicated math needs to be avoided at all costs. Not all gamers are computer science or science/engineering students. There's nothing so aggravating as playing 2nd edition DnD with a guy for the better part of 10 years and he still can't figure out the math for THAC0.

it doesn't necessarily need to be avoided, just avoided where possible and backed up with tables where it's not.

I agree with both MFB and Cheops here. I'm not dumb, I'm reasonably smart, but I suck with math. I wouldn't want that getting in the way of my game. Seriously, has anyone tried designing cranial cyberdecks with the old Shadowtech rules? It gets ugly, fast.

I've learned to hate and fear complex math when it tries to involve itself in my fun.