Number Puzzle – Solve the 4×4 Sliding 15-Puzzle
Slide one neighboring tile into the empty space at a time and restore numbers 1–15 while watching both move count and solve time.
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Number Puzzle
About Number Puzzle
Number Puzzle is the classic 4×4 sliding format with fifteen numbered tiles and one empty space. It does not randomize the board arbitrarily: the Shuffle routine performs 200 legal moves from a solved position, which preserves reachability.
The page tracks two practical measures—Moves and Time. Correctly placed numbers are colored green, giving immediate feedback even before the whole board is solved.
How to Play Number Puzzle
1Tap a numbered tile that is directly adjacent to the empty cell.
2The selected tile slides into the empty space and the empty position moves to the tile's old location.
3Continue arranging the board until numbers 1 through 15 are in order.
4Use Shuffle for another solvable board with Moves and Time reset to zero.
Number Puzzle Rules
- The board is 4×4 with 15 numbered tiles and one empty cell.
- Only orthogonally adjacent tiles can move into the empty cell.
- Every valid move adds 1 to Moves.
- The puzzle ends when all 15 numbers are in the solved order.
Number Puzzle Measures
| Action | Measure | How it works |
|---|---|---|
| Board | 4×4 / 15 numbered tiles | — |
| Shuffle | 200 legal moves | The board is scrambled by valid neighbor moves, so the generated position remains reachable from the solved state. |
| Move count | +1 per valid tile move | — |
| Timer | 1-second increments | — |
Number Puzzle Game Mechanics
Objective
Restore the numbers 1 through 15 to order on a 4×4 sliding board while tracking moves and solve time.
Round End
The puzzle is solved when tiles 1 through 15 occupy their target positions with the empty cell last.
- Only a tile directly above, below, left or right of the empty cell can move.
- A tile turns green when its value already matches its target position.
- Shuffle resets both the move counter and timer and generates another solvable state by performing 200 valid moves.
- Moves and time are shown for the current puzzle only; no best result is saved after reload.
Tips & Strategies
- Solve the first row and left-side structure progressively instead of moving random tiles toward their number.
- Watch which tiles are already green and avoid disturbing correct sections unless needed to route the empty cell.
- Use Moves to compare efficiency and Time to compare speed; they measure different aspects of a solve.
Game Info
| Game Name | Number Puzzle |
| Category | Puzzle |
| Difficulty | Medium |
| Platform | Web Browser |
| Price | Free |
| Players | 1 Player |
| Controls | Mouse / Touch |
| Last Updated | 2026-08-07 |
Frequently Asked Questions
Is this a 15-puzzle?
Yes. It uses a 4×4 board with fifteen numbered tiles and one empty cell.
Is every shuffled Number Puzzle solvable?
The game shuffles by performing 200 legal moves from the solved state, so the resulting board remains reachable by legal moves.
What counts as a move?
Only a numbered tile directly next to the empty cell can move, and each such move adds 1 to the move counter.
Does Number Puzzle save a best time?
No. Moves and solve time are only kept for the current puzzle session.
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