• The VOIDRUNNER'S CODEX is coming! Explore new worlds, fight oppressive empires, fend off fearsome aliens, and wield deadly psionics with this comprehensive boxed set expansion for 5E and A5E!

How much math should RPGs require?

log in or register to remove this ad


Guide of Modos
What? No square root or exponential calculation? But how are you going to do realistic fall damage and calculate the dragon’s speed after five rounds of constant deceleration?!? Think of my suspension of disbelief man! I can only abstract so much!!!
Dragons totally deserve harder maths. What better way to say, "you're fighting a dragon," than by squaring their attack and damage rolls?

In general - I'd suggest checkign the math standards for upper elementary. Grade 6, ages 11-13.
I... think you nailed it. This doc looks like it belongs in a players' handbook. Especially this part:

Reason abstractly and quantitatively.
• represent a situation symbolically and carry out its operations
• create a coherent representation of the problem
• translate an algebraic problem to a real world context
• explain the relationship between the symbolic abstraction and the context of the problem
• compute using different properties
• consider the quantitative values, including units, for the numbers in a problem

Here's where I'm torn, though. Board games typically minimize maths or use tools, like dice, to simplify operations. I consider this a carryover from earlier boardgames that were designed for kids or for entire families. Most (nerdy?) adults should be just as good at 6th grade Alaskan math as 4th grade-anywhere-math. So can we squeeze a little more out of our RPGs by asking a bit more (whoa - sixth grade) of the players' math efforts?

Again, what are we gaining out of these additional maths?

Generally increased detail and granularity in the game.
More interesting and more varied mechanics.
Improved resource management.
More accurate simulation; increased versimilitude.
Opportunities for more interactions across different parts of the game.
Broadening the "sweet spot" associated with ideal levels of play and modifications to "bounded accuracy".
And some of us just plain enjoy a higher level of complexity.


I may be in the minority, but to me, the worst thing a game can do is waste my time. Multiple rolls to do a single thing, a complicated table I have to flip to, or - excessive math.

I love Savage Worlds, but we stopped playing it due to the excessive amount of modifiers and math that can go into a single turn (don't get me started about the Two-Gun Kid or Two-Fisted Edges).

I prefer up-front math; ie, Call of Cthulhu asks players to do some math at character creation to assign the normal, hard, and extreme values for their skills (Hard = 1/2, Extreme = 1/5). I'm okay with this, because in session, rather than saying - "this is a Hard check, so you'll need to reduce your skill by half!" the math has already been done. The player just checks their sheet and the game moves forward.

I'll note that I play with two large groups (6 people in both groups), and we play in-person, so there is zero automation going on. I know it might seem minor, but that time debt really stacks up and can drag a game down.
Last edited:

Edgar Ironpelt

There's an old post from the USENET days about "Human Factors in game design." It's long, so I'll only post the whole thing if requested, but it does have a section concerning math:

o mathematical operations and modifiers

Many systems "modify" die rolls in some way. This can be a significant
step. First, you need to identify the appropriate modifier which puts
us back up at the "identifying the mechanic" step, here modified to
be "identifying the modifier". If modifiers are fixed, this requires
a rule book look-up and/or a reference sheet look-up. If the modifiers are
more flexible or subjective, the GM has to pause to think about it
(generally faster than a look up). The time spent on these add up
so the more you have, the longer it takes.

With respect to math, addition is the fastest. Subtraction and small
multiplications are the next best. Division is, by far, the worst.
Do some assembly language programming if you don't know why :). Avoid
division at all costs unless it something done outside of game play
(e.g. at character generation time). Multiplication are subtraction
can be OK if done once. In generally, you should try to stick with
addition only if you can.

The other major mathematical consideration is the size of the numbers
you are dealing with. Most people can quickly add numbers below ten
and fairly easily add numbers up to 20 or 30. Double digits, of
course, take more time. Subtraction and multiplication become more of
a problem in double digits and should be avoided. Division, as stated
above, should be avoided at all costs except, perhaps, division by 2,
3, 4, or 5. Any higher math (powers beyond squared or cubed, algebra
plug-ins, differentials, etc.) shouldn't even be considered. In
short, the smaller the numbers are and the less you do with them, the
faster it goes. If players need a calculator to resolve things, I'd
say that you've failed to produce a reasonable play-time mechanic.
EDIT: I should note that the post is not by me. It's something I agreed with, found useful, and saved as a reference.
Last edited:

Remove ads