Number Sudoku - Free Printable

Let’s solve the Sudoku puzzle step by step.

We are given a 4x4 grid divided into four 2x2 boxes (mini-grids). The rules:
- Each row must have numbers 1, 2, 3, 4 — no repeats.
- Each column must have numbers 1, 2, 3, 4 — no repeats.
- Each 2x2 box must have numbers 1, 2, 3, 4 — no repeats.

Here’s the starting grid:

Row 1: 3 | 1 | ? | ?
Row 2: | 2 | ? | ?
Row 3: | | 2 | ?
Row 4: | | 1 | 3

Let’s label positions as (row, column):

(1,1)=3, (1,2)=1
(2,2)=2
(3,3)=2
(4,3)=1, (4,4)=3

We need to fill in the blanks.

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Step 1: Look at Row 1: [3, 1, ?, ?] → missing 2 and 4.

Look at Column 3: has (3,3)=2 and (4,3)=1 → so far: 2, 1 → missing 3 and 4.

But Row 1 already has 3 and 1 → so for (1,3), it can’t be 3 or 1 → possible: 2 or 4.

But Column 3 already has 2 (at row 3) → so (1,3) cannot be 2 → must be 4.

Then (1,4) must be 2 (since Row 1 needs 2 and 4, and we put 4 in col3).

So now:

Row 1: 3 | 1 | 4 | 2

Check Column 4: currently has (1,4)=2, (4,4)=3 → so far: 2,3 → missing 1,4.

Now look at Row 2: [?, 2, ?, ?]

We know (2,2)=2.

Column 1: has (1,1)=3 → so far only 3 → missing 1,2,4.

But Row 2 already has 2 → so (2,1) can’t be 2.

Also, Box 1 (top-left 2x2): cells (1,1)=3, (1,2)=1, (2,1)=?, (2,2)=2 → so this box has 3,1,2 → missing 4.

Therefore, (2,1) must be 4.

Now Row 2: [4, 2, ?, ?]

Missing in Row 2: 1 and 3.

Look at Column 3: current values: (1,3)=4, (3,3)=2, (4,3)=1 → so far: 4,2,1 → missing 3.

So (2,3) must be 3.

Then (2,4) must be 1 (to complete Row 2: 4,2,3,1).

Now check Column 4: (1,4)=2, (2,4)=1, (4,4)=3 → so far: 2,1,3 → missing 4 → so (3,4) must be 4.

Now Row 3: [?, ?, 2, 4]

Missing in Row 3: 1 and 3.

Look at Column 1: current: (1,1)=3, (2,1)=4 → so far: 3,4 → missing 1,2.

Row 3 needs 1 and 3 → but Column 1 already has 3 → so (3,1) can’t be 3 → must be 1.

Then (3,2) must be 3.

Now Row 4: [?, ?, 1, 3]

Missing: 2 and 4.

Column 1: current: (1,1)=3, (2,1)=4, (3,1)=1 → so far: 3,4,1 → missing 2 → so (4,1) must be 2.

Then (4,2) must be 4.

Final grid:

Row 1: 3 | 1 | 4 | 2
Row 2: 4 | 2 | 3 | 1
Row 3: 1 | 3 | 2 | 4
Row 4: 2 | 4 | 1 | 3

Check all rows, columns, and 2x2 boxes — each has 1,2,3,4 exactly once. ✔

The two question marks in the original problem were in Row 1, Columns 3 and 4 → which we found to be 4 and 2.

But wait — looking back at the image description: the first blank grid shows:

3 1 ? ?
2 ? ?
2 ?
1 3

And the text says: “we will begin by looking at the third column... replace the two question marks with a 3 and 4... top square must be a 3”

Wait — that contradicts our solution? Let me re-read the user’s provided text.

Actually, the user included text from the worksheet:

> We will begin by looking at the third column. We already have the numbers 1 and 2 in that column, so we need to replace the two question marks with a 3 and 4. We can't put a 3 in the top square because there is already a 3 in that row. So the top square down must be a 4 and the next square down must be a 3. That's a good start!

Ah — so according to the worksheet’s own explanation, they’re saying:

In Column 3: existing numbers are 1 and 2 → so missing 3 and 4.

Top of Column 3 is Row 1, Col 3 → Row 1 already has 3 → so can’t put 3 there → must put 4.

Then Row 2, Col 3 must be 3.

That matches what I did.

Then they say: “the top square down must be a 4 and the next square down must be a 3” — meaning (1,3)=4, (2,3)=3.

Which is what we have.

Then they don’t finish the rest — but we did.

So the two question marks in the first row are 4 and 2.

But let’s confirm the exact question.

Looking at the image description again — the user didn’t ask a specific question, but the task is to solve the Sudoku puzzle shown.

Since the worksheet starts solving it and leaves it incomplete, and the user says “solve the problem accurately”, we should provide the full solved grid.

But perhaps the immediate question is just to fill the two question marks in Row 1?

The text says: “replace the two question marks with a 3 and 4” — but actually, in Row 1, the two question marks are in columns 3 and 4.

Column 3: as above, must be 4 (because row 1 has 3 already, and column 3 has 1,2 below).

Column 4: Row 1 has 3,1 → so missing 2,4 → but column 4 has (4,4)=3 → and later we’ll see it needs 2.

From our full solution: (1,3)=4, (1,4)=2.

But the worksheet text says: “replace the two question marks with a 3 and 4” — that might be referring to the two question marks in Column 3? But in the grid shown, Row 1 has two question marks, and Row 2 also has two, etc.

Actually, rereading: “looking at the third column. We already have the numbers 1 and 2 in that column, so we need to replace the two question marks with a 3 and 4.”

In the grid, Column 3 has:

Row 1: ?

Row 2: ?

Row 3: 2

Row 4: 1

So yes, two question marks in Column 3: rows 1 and 2.

They say: can’t put 3 in top (row1) because row1 already has 3 → so row1,col3 = 4; row2,col3 = 3.

So those two are filled.

Then the other question mark in Row 1, column 4 — not mentioned yet.

But since the user said “solve the problem”, and the problem is the whole puzzle, we should give the full answer.

However, to match the format, and since the initial focus was on those two, but ultimately we solved everything.

Perhaps the final answer expected is the completed grid.

But let’s see the instruction: “Provide only the final correct answer”

Since it’s a Sudoku, probably the filled grid.

But to be precise, let’s output the grid as the answer.

Alternatively, if the question is implied to be “what goes in the two question marks in row 1?”, then it’s 4 and 2.

But the worksheet text talks about replacing two question marks in column 3 with 3 and 4 — specifically, (1,3)=4, (2,3)=3.

Then it doesn’t mention the fourth cell in row 1.

But in the grid, row 1 has two question marks: col3 and col4.

After putting 4 in col3, col4 must be 2, as row 1 needs 2 and 4, and 4 is used.

So both are determined.

I think the safest is to provide the full solved grid.

But let me double-check my solution against the constraints.

Grid:

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

Rows: each has 1,2,3,4 — good.

Columns:

Col1: 3,4,1,2 — good
Col2: 1,2,3,4 — good
Col3: 4,3,2,1 — good
Col4: 2,1,4,3 — good

Boxes:

Top-left: 3,1 / 4,2 → 1,2,3,4 — good
Top-right: 4,2 / 3,1 → 1,2,3,4 — good
Bottom-left: 1,3 / 2,4 → 1,2,3,4 — good
Bottom-right: 2,4 / 1,3 → 1,2,3,4 — good

Perfect.

So the solved puzzle is as above.

Now, for the Final Answer, since it’s a grid, I’ll write it clearly.

Final Answer:
3 1 4 2
4 2 3 1
1 3 2 4
2 4 1 3