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One table, several questions

Part B · L07 · 5–10 minutes · Prerequisite: L06

The situation and question

Keep the D&D 2014 ordinary ability check from L06, with a total bonus of +5. How often would it meet DC 10, 15, or 20? These are three alternative difficulty settings, not three successive checks or three opponents.

Predict

Should the three probabilities add to 100%? A total of 20 meets all three thresholds. The questions overlap, so there is no reason for their sum to be one.

Build

Square brackets make a list: an ordered collection of values. Here, each value is a labelled pair. Parentheses around ("Meet DC 10", chance) group the label and its probability into a two-item tuple. A comma separates the items; commas also separate the rows. Tuples keep the two parts of a row together.

prob_table(rows) turns that list into one probability table. output still presents the result. Every row's second item must be a probability between 0 and 1—not a mean, count, or percentage multiplied by 100. The table formats it for you.

bonus = 5
check = d(20) + bonus
rows = [
    ("Meet DC 10", check.p_ge(10)),
    ("Meet DC 15", check.p_ge(15)),
    ("Meet DC 20", check.p_ge(20)),
]
output("One ability check, alternative difficulties", prob_table(rows))

One ability check, alternative difficulties · Table

Run and read

The rows should be 80%, 55%, and 30%. For DC 10, natural faces 5–20 succeed: sixteen of twenty. The other counts are eleven and six of twenty. Their sum is 165%, which is fine: they are separate, overlapping questions, not exclusive outcomes. Do not multiply them to infer a chance of meeting all three with one roll. On that same roll, meeting DC 20 already meets the others.

Change one thing

Add a fourth row for DC 25 inside the list. Keep its label consistent with its query. Check: the new row is 5%, one natural face out of twenty.

Try it yourself

Build a two-row table for a single unmodified d6: “Exactly six” and “Four or more.” Answer check: .pmf(6) gives 1/6 and .p_ge(4) gives 1/2. These also overlap. You have assembled a report from a question, not simulated rolls.

What you now know

A list of labelled probability questions makes a compact comparison. A report must say whether rows are categories, alternative settings, or overlapping events.

Rules and model notes

D&D Basic Rules 2014, Using Ability Scores, Ability Checks and Typical Difficulty Classes, checked 2026-09-15. Same scope as L06: one ordinary check, fixed total bonus, no attack exceptions, advantage, rerolls, or special features. A harder DC changes the query, not the die.

Where next

Previous: averages and chances · Next: a loop. The ordinary ability-check recipe uses tables to keep related questions in one report.

Content ID: L07 · Review status: pilot

Prerequisites: L06

Rules review: source checked 2026-09-15; human review pending