A sudoku that draws a random grid is useless in class. InZeDoku does not store its grids: it
builds them from a number, and the same number always gives back the same
grid, on any device. So a grid is designated by a short string instead of being carried
around. On a whiteboard, interactive or simply projected, the grid is filled in by
hand, with a marker, in front of the class: no phone, nothing to draw — you fill it
in, wipe it, move on to the next one.
3+4+6+35+6+7+5+1
8+5+36+8+6+6+1
Explore Reason Share
One code, one grid
Every grid has a game code — G4CS41OP-a30y6s-IU — carrying the mode,
the geometry, the size, the level, the options and the seed. Typed on another device, it gives
back exactly the same grid. A check key refuses any typo: better a “code not
recognised” than a neighbouring grid, silently.
The QR on the board
You project the grid, the class taps Code → Scan a QR, aims at the board, and
everyone has the grid. Twenty-five pupils in one minute, nothing dictated, nothing spelled out.
The camera is only requested at that moment, never at install time, and the image is decoded on
the device.
Marking without collecting
The state code carries the game as it stands — values, pencil marks, empty cells.
Pasted onto the projected screen, it is a line of reasoning you read, not a mark. Printing
produces the blank grid to photocopy, the answer key on request, and the
player's path move by move, with the rule that applied.
Stuck in front of the class? Two sheets, when printing
The full version adds two pages when printing. The first says how the grid could be solved; the second, how the pupil actually solved it. In front of a projected grid that will not budge and twenty-five pairs of eyes waiting, the first is the way out: read the next step, show it, move on, without losing the class or the time. With a pupil's work, the second is the marking: you see where the reasoning slipped, and from where. To get unstuck on a single cell, the game's light bulb 💡 is free.
See examples of guidance
The solving list
Cell by cell, in the order they can be found, each with the rule that unlocks it. The sheet says so at the top: it is one path among others — several techniques may apply at every step, and a pupil who proposes another one is not wrong. On a grid that logic alone cannot finish, it stops and says how many cells remain.
Solving list — 4×4 Calcudoku, four operations
D2 = 2 — row 2 must contain a 2; it is ruled out in A2, B2, C2, only D2 is left
C3 = 1 because
column D already holds 2
the 5+ cage on C3, D3, D4
D3 = 3 because
row 3 already holds 1
column D already holds 2
the 5+ cage on C3, D3, D4
D4 = 1 — the 5+ cage on C3, D3, D4: only 1 is left
D1 = 4 — column D already holds 1, 2, 3: only 4 is left
C1 = 3 — the 9+ cage on C1, D1, D2: only 3 is left
C2 = 4 because
row 2 already holds 2
column C already holds 1, 3
C4 = 2 — column C already holds 1, 3, 4: only 2 is left
B3 = 4 because
row 3 already holds 1, 3
the 24× cage on B3, B4, C4
A3 = 2 — row 3 already holds 1, 3, 4: only 2 is left
A4 = 4 — the 2− cage on A3, A4: only 4 is left
B4 = 3 — the 24× cage on B3, B4, C4: only 3 is left
A1 = 1 because
column A already holds 2, 4
the 2: cage on A1, B1
B1 = 2 — the 2: cage on A1, B1: only 2 is left
B2 = 1 — column B already holds 2, 3, 4: only 1 is left
A2 = 3 — the 12× cage on A2, B2, C2: only 3 is left
As printed by the app, cell by cell, with the rule that unlocks each one.
The player's path
The game replays the pupil's moves in order and names the rule that applied to each. It only says “error” under one strict condition: the value placed makes the grid impossible to finish. Here, a game in progress — seven moves, an error on the seventh, the grid unfinished. The faulty move is set aside and what follows is judged without it: a pupil often slips in one place and reasons perfectly on the rest.
Player's path — game in progress, 1 error
D2 = 4 because
row 2 already holds 1, 2
the 2: cage on D2, D3
D3 = 2 — the 2: cage on D2, D3: only 2 is left
D1 = 1 — column D already holds 2, 3, 4: only 1 is left
C1 = 4 — the 5+ cage on C1, D1: only 4 is left
C2 = 3 — row 2 already holds 1, 2, 4: only 3 is left
C4 = 2 — column C must contain a 2; it is ruled out in C3, only C4 is left
A3 = 1 — ERROR: from here on the grid can no longer be completed
1 error. A move flagged as an error is set aside for what follows: everything after it is judged without it.
Everything the dossier of teaching proposals describes is played in the free version — it is calibrated for that — checked
automatically at every release of the game, along with the codes themselves. Nothing to prepare on the
school's side, nothing for parents to sign: the game asks for no account and collects nothing.
A question about InZeDoku?
To discover the game, prepare to use it in class or discuss a project, talk with Jacques Lovi.
When booking, mention InZeDoku and the purpose of your meeting.
