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Fate Core — four Fate dice
R12 · Intermediate · Scoped component
Question and scope
Fate Core rolls four Fate dice, each with two minus, two blank, and two plus faces. What is the range of their total? Predict whether four pluses is as likely as a total of zero.
Source sections are linked under Rules below; primary-source review is recorded in the release dossier. Independent human and browser/usability review are separate gates.
Inputs and model limits
Four independent Fate dice. No skill, opposition, or invocation yet; this preserves the old 4dF URL with an explicit Fate Core scope.
Complete runnable model
die_faces([-1, -1, 0, 0, 1, 1]) assigns equal weight to each entry, including duplicates. A minus sign makes a number negative. Adding the die four times combines independent rolls; it does not force all four dice to show the same sign.
fate_die = die_faces([-1, -1, 0, 0, 1, 1])
roll = fate_die + fate_die + fate_die + fate_die
output("Four Fate dice", roll)
output("All pluses", roll.pmf(4))
output("Zero total", roll.pmf(0))
Four Fate dice · DieRoll · mean 0.000
| outcome | % | frac | X/81 |
|---|---|---|---|
| -4 | 1.23 | 1/81 | 1 |
| -3 | 4.94 | 4/81 | 4 |
| -2 | 12.3 | 10/81 | 10 |
| -1 | 19.8 | 16/81 | 16 |
| 0 | 23.5 | 19/81 | 19 |
| 1 | 19.8 | 16/81 | 16 |
| 2 | 12.3 | 10/81 | 10 |
| 3 | 4.94 | 4/81 | 4 |
| 4 | 1.23 | 1/81 | 1 |
All pluses · Prob
| outcome | % | frac | X/81 |
|---|---|---|---|
| All pluses | 1.23 | 1/81 | 1 |
Zero total · Prob
| outcome | % | frac | X/81 |
|---|---|---|---|
| Zero total | 23.5 | 19/81 | 19 |
Reading the report and independent checks
The possible range is exactly −4 to +4. Mean is zero. Each extreme has probability (1/3)^4 = 1/81; zero is 19/81. There are 3^4 equally likely sign sequences even though the physical dice have six faces.
Safe changes
Replace the face list with [-1, 0, 1]. Nothing changes: all three signs still have equal weight. Replacing it with [-1, 0, 1, 1] would make plus twice as likely as either other sign.
Composition and boundary checks
Build a two-Fate-dice report. Answer: probabilities 1/9,2/9,3/9,2/9,1/9 at −2 through +2. Repeated entries describe weights, not outcomes to add together.
Do not combine separate marginal reports and assume they preserve the same rolled faces. When an event depends on several properties of one roll, keep those properties together inside a single classifier or pool callback.
Rules
Fate Core SRD, dice and the ladder. Four independent Fate dice; their faces are equally weighted −1, 0, +1. Other Fate/Fudge variants are not implied.
Related learning
Lesson L17 explains the modelling idea step by step. Cookbook index offers both game and mechanic views of these same recipes.
Content ID: R12 · Review status: pilot
Prerequisites: L17