B-first neutral own job · staff judgement
Actual source reading may familiarise the paper scene neutrally. Record actual instruction/support and teach before using a component. Later is a new offer after a real teaching interval; no universal familiarity or progress is claimed.
Whole neutral source
Fictional paper scene: First costume-label scene. There are 4 columns A to D, left to right, and 4 rows 1 to 4, top to bottom. All cells have the same size. Up/down mean towards the top/bottom of this page; left/right across this page. One move reaches one neighbouring cell, never a diagonal. Start: B2. Target: D3. The name-card is at A1; the spare-card is at D4. Closed cells: C2. Do not enter or pass through them. Proposed instruction: 2 cells right, then 1 cell down. A supplied helper says: “Reaching D3 would make the whole proposed route legal.” This is a supplied scene. Read its whole legend before the questions; it is not a real place, a measured route or an observed journey.
B-first-Q1
Name or mark the supplied start and target positions.
Criterion
Identifies start B2 and target D3 using the declared row/column labels.
After-own staff possibility
Start B2; target D3.
Teach this relationship, check actual opportunity and receive own words before staff models. Later requires a real teaching interval, not a day label.
B-first-Q2
Which first attempted one-cell move in the proposed instruction would enter a closed cell? Name that cell.
Criterion
Identifies C2 as the first closed cell the proposed instruction attempts to enter; distinguishes an attempted step from an actual legal journey.
After-own staff possibility
The first right move attempts C2; it is closed. Stop a legal traversal before entering it.
Teach this relationship, check actual opportunity and receive own words before staff models. Later requires a real teaching interval, not a day label.
B-first-Q3
Give a complete legal route from the supplied start to the target that avoids the closed cell.
Criterion
A complete orthogonal route starts at B2, stays inside the grid, avoids C2 at every step and ends at D3; no shortest-path requirement.
After-own staff possibility
1 cell down, then 2 cells right; positions B2, B3, C3, D3.
Teach this relationship, check actual opportunity and receive own words before staff models. Later requires a real teaching interval, not a day label.
B-first-Q4
Does the supplied helper claim establish that the whole proposed route is legal? Use the full route and closure rule to explain.
Criterion
Rejects endpoint-only proof: the proposed path attempts C2, which is expressly closed. An endpoint match does not establish the legality of its preceding path.
After-own staff possibility
The endpoint can be D3 in a geometric replay, but the proposal passes through closed C2. It is not a legal journey.
Teach this relationship, check actual opportunity and receive own words before staff models. Later requires a real teaching interval, not a day label.
Answers/criteria/fullNEXT/adult models remain staff-only. Complete source facts/labels and supplied helper claim are neutral input, not prefilled child responses.
