Number Puzzle Printable for Adults (2 Free Grids)

Two complete number fill puzzles on this page, with the rules printed next to each one and the full solution a tap away. Both grids are small enough to finish with a pencil, and both were run through a solver that confirms exactly one way to fill them in. Hit Ctrl+P (Cmd+P on Mac) if you want them on paper. No download, no email, no sign-up.

How to use this page: solve on screen or print. The solution blocks stay collapsed until you tap them, so no accidental spoilers while you work. Printing keeps the solutions visible at the bottom, so fold the sheet over if you are bringing these to a table. If you want a different flavor, the free logic puzzles page works the same way with detective cases.

Puzzle 1 — Grid Fill 4×4

Rules

Fill the grid with the digits 1 to 4. Every row must contain 1, 2, 3 and 4 exactly once. Every column must contain 1, 2, 3 and 4 exactly once. That is the whole rule set. Six digits are printed to start you off.

			3
4
2		1
3	4

Solution and how it falls out

1	2	4	3
4	1	3	2
2	3	1	4
3	4	2	1

No guessing needed anywhere. The chain, in order:

Column 1 already holds 4, 2 and 3, so its last blank must be 1.
Row 3 then needs 3 and 4. Column 4 already has a 3, so the 4 lands there and the 3 goes beside it.
Row 1 needs 2 and 4. Column 2 already holds a 4, so 2 goes in row 1, and 4 completes the row.
Column 2 is now missing only a 1, which lands in row 2. Row 2 needs 2 and 3; column 4 already has a 3, so 2 goes there and 3 fills row 2.
Column 3 is down to one blank, which takes the 2. The last cell takes the 1.

Puzzle 2 — Grid Fill 5×5 with a Diagonal Rule

Rules

Fill the grid with the digits 1 to 5. Every row must contain all five digits exactly once, and every column too. One extra rule: the five cells on the main diagonal, running top-left to bottom-right, must all hold different digits. Those cells carry a thicker border. Nine digits are printed.

			3
1		3
		2		1
2	3
5			4

Solution and how it falls out

4	1	5	3	2
1	5	3	2	4
3	4	2	5	1
2	3	4	1	5
5	2	1	4	3

The diagonal does real work here. The chain:

Row 3 needs 3, 4 and 5. Column 4 already holds 3 and 4, so its blank in row 3 takes the 5. The rest of row 3 follows: 4 into column 2, 3 into column 1.
Column 1 now misses only a 4, which lands in row 1. That cell sits on the diagonal, so the diagonal still owes 1, 3 and 5 to rows 2, 4 and 5.
Row 2 needs 2, 4 and 5. Its diagonal cell cannot take 2 or 4 (both belong to the diagonal set already placed), so it takes 5. Then 2 and 4 fill the row ends.
Column 4 is down to one blank, which takes 1. That was the second diagonal cell, leaving 3 for the bottom-right corner.
Row 4 needs 4 and 5. Column 5 already holds a 5, so 5 goes there and 4 completes row 4.
Row 5 needs 1 and 2. Column 3 takes the 1 (it already holds a 5), then column 2 takes the 2.
Row 1 now needs 1 and 2. Column 2 takes the 1, and 2 completes the top row.

Three opinions from making these

Start from the fullest line, not the top row. On both grids the fastest path runs through the row or column with the most printed digits. Working top-down wastes the opening minutes on lines that give you nothing.
Pencil tiny candidates in the corners. Holding three possibilities in your head while you check a column is how errors get in. Write the 1–2 pencil marks, let the grid carry them, erase as cells resolve.
On the 5×5, touch the diagonal early. My take: the diagonal rule pins cells that plain row logic leaves open, and solvers who save it for last end up redoing half the grid. Use it as a third voice, not a footnote.

A straight note on difficulty

These two sit at the easy end on purpose. The 4×4 is a coffee-break warm-up, five minutes or so. The 5×5 with the diagonal runs longer, maybe ten to twenty depending on how the diagonal lands for you, but it stays gentle. Neither needs guessing: each grid has exactly one completion, and a small Python solver counted every possible fill to confirm that before the puzzles went up. If a grid could be finished two ways, it got thrown out and rebuilt.

If you want harder, that is what the paid book is for. The grids there get bigger and the three-star cases at the back are genuinely stubborn.

Want 60 more? Case Files: 60 Detective Logic Puzzles

The full book wraps 60 case files in a detective frame from the Grayharbor night desk. Same promise as this page: every case was generated solution-first, with a solver checking that the printed clues allow only one answer. Five kinds of detective work, full answer keys at the back for A4 and Letter PDFs both included.

Pages	Part	What it is
3-22	Logic Grids (cases 001-020)	Elimination tables, 3-4 suspects, items/places/times/details
23-37	Coded Notes (cases 021-035)	Caesar shifts, atbash, keyword ciphers, number codes
38-47	Witness Matches (cases 036-045)	Statements from a scene, match each person to what they carried and where they stood
48-57	Timelines (cases 046-055)	Six events, rebuild the order from time clues
58-62	Final Cases (cases 056-060)	Five suspects, one thief, profile table plus statements
63-65	Answer Keys	Full solutions for all 60 cases

Get the full puzzle book - 60 detective logic puzzles →

one-time · 65 pages, A4 + Letter PDFs · full answer keys · or browse the catalog first

More free printables: three free detective cases, logic puzzle printables, and free printable mazes.