Tree diagrams

When a choice is followed by another choice, a tree shows every path through them. Each level is one decision, each branch is one option, and every complete path from top to bottom is one outcome. Counting the ends of the branches counts the outcomes.

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Work through it

LearnWhat it is, how to spot it, a worked example, and where it goes wrong.
Practice — 3-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Practice — 4-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Practice — 5-point ladderNo problems written at this tier yet.Nothing written at this tier yet
Skill quizFinish every ladder that has problems first.Finish the ladders above first

Before and after

Needs first

CNT-01Systematic listing

Opens up

CNT-03The multiplication principle

In official papers

No indexed official paper question has been tagged with CNT-02 yet. The index grows one paper at a time, and it records only question numbers, point values and our own skill tags — never the problems themselves.

See the papers indexed so far

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