Proof and counterexample artifacts

Produce a visible example, counterexample, or short proof artifact that justifies or rejects a mathematical claim.

Surface

This skill appears in Clue-card candidate choice, Candidate elimination markboard, Violated-clue marker, Ambiguity repair clue choice, Minimal clue set choice, Grid consistency repair, List missing or duplicate repair, Parity pairing proof choice, Invariant move legal-illegal mark, Truth card verifier, Proof card evidence choice, Counterexample card build-select, Contradiction clue mark, Pigeonhole box guarantee choice, Invariant game challenge choice, Connected grid exact-cover partition and count, Unique violated predicate and matching repair pair, Place-value property case-count entry, Conserved-component final-whole entry, Unique-perfect-matching edge extremum proof, Sequential epistemic ordered-value choice, Orthogonal-grid removal counterexample strategy, Geometric network minimum-cost entry, Bounded semantic rubric response, Bounded reasoning proof workspace, Switch-bulb one-visit identification, Equal-rope knot-bundle choice, Embedded-graph predicate panel choice, Equal-sum pair omission choice, Finite-constraint entailment choice, Region-doorway trail-start choice, Symbol-strip deletion middle token, Plus-minus target minus-count choice, Card-operation move-count pair choice, Embedded-graph triangle count with exhaustive witness proof, Segment relocation shape transform, Layered-path consistency proof, Transport-crossing sequence proof, Word-ladder path or no-path proof, Segment-relocation equation repair.

Task formats

Ambiguity repair clue choice

Ambiguity repair clue choice asks the player to choose a clue action that changes an ambiguous clue set into a valid unique solution.

ActionChoose a clue action that changes an ambiguous clue set into a valid unique solution.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Bounded reasoning proof workspace

Bounded reasoning proof workspace asks the player to assemble or enter an ordered, editable sequence of claim-and-reason steps that establishes a bounded mathematical characterization from declared givens, then submit the exact terminal family/value fields.

ActionAssemble or enter an ordered, editable sequence of claim-and-reason steps that establishes a bounded mathematical characterization from declared givens, then submit the exact terminal family/value fields.
CheckComplete the bounded reasoning proof workspace action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Bounded semantic rubric response

Bounded semantic rubric response asks the player to submit a concise explanation using the required mathematical claims, relations, or evidence tags in a bounded response schema.

ActionSubmit a concise explanation using the required mathematical claims, relations, or evidence tags in a bounded response schema.
CheckComplete the bounded semantic rubric response action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Candidate elimination markboard

Candidate elimination markboard asks the player to mark candidates eliminated by a highlighted clue or all clues.

ActionMark candidates eliminated by a highlighted clue or all clues.
CheckComplete the candidate elimination markboard action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Card-operation move-count pair choice

Card-operation move-count pair choice asks the player to determine the exact numbers of allowed swaps and flips in an exactly-three-move solution, then choose the ordered pair (swaps, flips).

ActionDetermine the exact numbers of allowed swaps and flips in an exactly-three-move solution, then choose the ordered pair (swaps, flips).
CheckComplete the card-operation move-count pair choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Clue-card candidate choice

Clue-card candidate choice asks the player to use clue cards to eliminate visible candidates and choose the single survivor.

ActionUse clue cards to eliminate visible candidates and choose the single survivor.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer / Challenge
ShowsIndependent solve / Supported solve / Challenge ready
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Connected grid exact-cover partition and count

Connected grid exact-cover partition and count asks the player to partition every active grid cell into equal-size connected regions, then enter the derived region count.

ActionPartition every active grid cell into equal-size connected regions, then enter the derived region count.
CheckMove or assign each object to the matching zone.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Geometry, shapes, and measurement

Conserved-component final-whole entry

Conserved-component final-whole entry asks the player to use a conserved component and changed composition fractions to enter the exact final whole in the declared unit.

ActionUse a conserved component and changed composition fractions to enter the exact final whole in the declared unit.
CheckComplete the conserved-component final-whole entry action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Math facts / times tables / Fractions feel hard

Contradiction clue mark

Contradiction clue mark asks the player to mark the clue, statement, or grid mark that contradicts the rest.

ActionMark the clue, statement, or grid mark that contradicts the rest.
CheckComplete the contradiction clue mark action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Counterexample card build-select

Counterexample card build-select asks the player to select or build one valid counterexample to disprove a claim.

ActionSelect or build one valid counterexample to disprove a claim.
CheckComplete the counterexample card build-select action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Embedded-graph predicate panel choice

Embedded-graph predicate panel choice asks the player to inspect exact graph panels and choose the single panel whose topology satisfies the stated object-relation predicate.

ActionInspect exact graph panels and choose the single panel whose topology satisfies the stated object-relation predicate.
CheckComplete the embedded-graph predicate panel choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Embedded-graph triangle count with exhaustive witness proof

Embedded-graph triangle count with exhaustive witness proof asks the player to inspect one fixed labeled straight-line graph, enter the total number of valid triangles, and submit the exhaustive set of each triangle's three corner labels.

ActionInspect one fixed labeled straight-line graph, enter the total number of valid triangles, and submit the exhaustive set of each triangle's three corner labels.
CheckComplete the embedded-graph triangle count with exhaustive witness proof action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Equal-rope knot-bundle choice

Equal-rope knot-bundle choice asks the player to compare exact shown cord lengths and knot effects, then choose the one candidate card consistent with equal starting lengths and identical positive per-knot cord use.

ActionCompare exact shown cord lengths and knot effects, then choose the one candidate card consistent with equal starting lengths and identical positive per-knot cord use.
CheckComplete the equal-rope knot-bundle choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing / Geometry, shapes, and measurement

Equal-sum pair omission choice

Equal-sum pair omission choice asks the player to pair the values to a common sum and choose the one omitted value that makes a complete equal-sum pairing possible.

ActionPair the values to a common sum and choose the one omitted value that makes a complete equal-sum pairing possible.
CheckComplete the equal-sum pair omission choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Math facts / times tables / Number sense and place value

Finite-constraint entailment choice

Finite-constraint entailment choice asks the player to use the explicit finite constraints to determine which target proposition holds in every valid assignment, then choose that proposition.

ActionUse the explicit finite constraints to determine which target proposition holds in every valid assignment, then choose that proposition.
CheckComplete the finite-constraint entailment choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Geometric network minimum-cost entry

Geometric network minimum-cost entry asks the player to interpret an exact geometric network domain, optionally construct a candidate, and enter the globally minimal length or cost in the declared unit.

ActionInterpret an exact geometric network domain, optionally construct a candidate, and enter the globally minimal length or cost in the declared unit.
CheckComplete the geometric network minimum-cost entry action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Geometry, shapes, and measurement

Grid consistency repair

Grid consistency repair asks the player to find and fix a wrong mark in a partially filled grid.

ActionFind and fix a wrong mark in a partially filled grid.
CheckComplete the grid consistency repair action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Invariant game challenge choice

Invariant game challenge choice asks the player to predict possible or impossible final state in a constrained move game using an invariant proof card.

ActionPredict possible or impossible final state in a constrained move game using an invariant proof card.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Layered-path consistency proof

Layered-path consistency proof asks the player to submit either a complete first-to-last topological witness order or a shortest directed contradiction-cycle certificate for declared layered-path constraints.

ActionSubmit either a complete first-to-last topological witness order or a shortest directed contradiction-cycle certificate for declared layered-path constraints.
CheckComplete the layered-path consistency proof action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

List missing or duplicate repair

List missing or duplicate repair asks the player to mark duplicate, missing, or illegal cases in a list.

ActionMark duplicate, missing, or illegal cases in a list.
CheckComplete the list missing or duplicate repair action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Minimal clue set choice

Minimal clue set choice asks the player to select the smallest sufficient clue set or mark a redundant or necessary clue.

ActionSelect the smallest sufficient clue set or mark a redundant or necessary clue.
CheckComplete the minimal clue set choice action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Orthogonal-grid removal counterexample strategy

Orthogonal-grid removal counterexample strategy asks the player to disprove a universal score guarantee in a centrally symmetric orthogonal-grid removal game by submitting a valid value assignment and a complete legal counter-strategy.

ActionDisprove a universal score guarantee in a centrally symmetric orthogonal-grid removal game by submitting a valid value assignment and a complete legal counter-strategy.
CheckComplete the orthogonal-grid removal counterexample strategy action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Parity pairing proof choice

Parity pairing proof choice asks the player to pair objects or choose a proof card to justify even, odd, or impossible.

ActionPair objects or choose a proof card to justify even, odd, or impossible.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Pigeonhole box guarantee choice

Pigeonhole box guarantee choice asks the player to choose the guaranteed conclusion from objects and boxes or capacities.

ActionChoose the guaranteed conclusion from objects and boxes or capacities.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Place-value property case-count entry

Place-value property case-count entry asks the player to count values in a finite range that satisfy a digit or place-value predicate and enter the exact cardinality.

ActionCount values in a finite range that satisfy a digit or place-value predicate and enter the exact cardinality.
CheckComplete the place-value property case-count entry action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Plus-minus target minus-count choice

Plus-minus target minus-count choice asks the player to choose how many mutable binary plus signs must be changed to minus signs, minimizing that count while making the fixed-order exact expression satisfy the declared target.

ActionChoose how many mutable binary plus signs must be changed to minus signs, minimizing that count while making the fixed-order exact expression satisfy the declared target.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Balanced growth

Proof card evidence choice

Proof card evidence choice asks the player to select the proof card that supports a visible claim.

ActionSelect the proof card that supports a visible claim.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Region-doorway trail-start choice

Region-doorway trail-start choice asks the player to interpret a complete undirected regions-and-doorways graph and select the unique start region for a trail using every doorway exactly once and ending at a named region.

ActionInterpret a complete undirected regions-and-doorways graph and select the unique start region for a trail using every doorway exactly once and ending at a named region.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Segment-relocation equation repair

Segment-relocation equation repair asks the player to relocate the permitted number of segments to make the displayed equation true and submit the normalized move-and-result state.

ActionRelocate the permitted number of segments to make the displayed equation true and submit the normalized move-and-result state.
CheckComplete the segment-relocation equation repair action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Balanced growth

Segment relocation shape transform

Segment relocation shape transform asks the player to relocate exactly two distinct unit segments from a fixed initial edge state and submit the move delta plus the complete resulting edge state.

ActionRelocate exactly two distinct unit segments from a fixed initial edge state and submit the move delta plus the complete resulting edge state.
CheckComplete the segment relocation shape transform action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Geometry, shapes, and measurement

Sequential epistemic ordered-value choice

Sequential epistemic ordered-value choice asks the player to use ordered public utterances about hidden ordered values to choose the uniquely forced target value.

ActionUse ordered public utterances about hidden ordered values to choose the uniquely forced target value.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Switch-bulb one-visit identification

Switch-bulb one-visit identification asks the player to determine a legal ordered switch strategy and use the one inspection to identify the complete switch-to-lamp correspondence.

ActionDetermine a legal ordered switch strategy and use the one inspection to identify the complete switch-to-lamp correspondence.
CheckComplete the switch-bulb one-visit identification action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Symbol-strip deletion middle token

Symbol-strip deletion middle token asks the player to apply the ordered deletion rule to the symbol strip and enter the uniquely determined remaining middle token.

ActionApply the ordered deletion rule to the symbol strip and enter the uniquely determined remaining middle token.
CheckComplete the symbol-strip deletion middle token action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Transport-crossing sequence proof

Transport-crossing sequence proof asks the player to construct and order a legal crossing sequence, then complete a bounded optimality-and-uniqueness certificate.

ActionConstruct and order a legal crossing sequence, then complete a bounded optimality-and-uniqueness certificate.
CheckComplete the transport-crossing sequence proof action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Truth card verifier

Truth card verifier asks the player to mark a visible statement as true, false, or not determined and choose evidence when required.

ActionMark a visible statement as true, false, or not determined and choose evidence when required.
CheckComplete the truth card verifier action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Unique-perfect-matching edge extremum proof

Unique-perfect-matching edge extremum proof asks the player to for a balanced finite bipartite graph constrained to have a unique perfect matching, submit the maximum edge count, an upper-bound certificate, and an attaining construction.

ActionFor a balanced finite bipartite graph constrained to have a unique perfect matching, submit the maximum edge count, an upper-bound certificate, and an attaining construction.
CheckComplete the unique-perfect-matching edge extremum proof action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Unique violated predicate and matching repair pair

Unique violated predicate and matching repair pair asks the player to evaluate a designated candidate, choose its unique failed predicate, then choose the repair that makes every predicate pass.

ActionEvaluate a designated candidate, choose its unique failed predicate, then choose the repair that makes every predicate pass.
CheckComplete the unique violated predicate and matching repair pair action.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Violated-clue marker

Violated-clue marker asks the player to given a proposed candidate or arrangement, mark the clue it breaks.

ActionGiven a proposed candidate or arrangement, mark the clue it breaks.
CheckChoose the answer that matches the visible prompt.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Word-ladder path or no-path proof

Word-ladder path or no-path proof asks the player to submit a valid finite word-ladder path under the declared mutation rule or a complete no-path certificate.

ActionSubmit a valid finite word-ladder path under the declared mutation rule or a complete no-path certificate.
CheckPick the path or next move that satisfies the rule.
UseSupport / Core / Transfer
ShowsCheck only
PresentationCompact / Standard / Extended

Practice focus

Word problems are confusing

Selection

Fresh independent work can move toward Core, Transfer, or Challenge routes; help use or confusion keeps support visible.

Help

Hints keep attention on the visible structure; reveals show the path without counting as independent evidence.

Presentation

Presentation can reduce reading and interaction load without changing the selected skill. Practice focus can bias compatible work without breaking prerequisites or story fit.

Story fit

  • story beats with visible logic state, manipulable evidence, and a bounded player action
  • episodes with visible movement, fitting, nets, layers, grids, routes, or solid viewpoints
  • episodes where two quantities are linked by an explicit multiplicative scale or conserved proportion
  • episodes with a real scale, instrument, duration, unit, rate, or money quantity