1. First Logic Steps — Grades 1–2
Grades 1–2 · Ages approximately 6–8 · 20–25 minutes
Prepared by Julia Goover, PuzzleGenerator team.
Learning goals
- Recognise numbers 1–4 and use each once in a row, column and 2×2 box.
- Explain one placement using evidence, rather than guessing.
Materials and preparation
Paper, a pencil and the grid below. Copy the student task separately from the answer key. No website, account or paid subscription is required to solve this task.
Teaching sequence
- Model (5 minutes): draw a 4×4 grid and outline its four 2×2 boxes. Demonstrate that a row with 1, 2 and 4 is missing 3. Explain that every placement must also fit its column and box.
- Guided start (5 minutes): inspect row 2. Its missing numbers are 2 and 3. The left 2×2 box already contains 1 and 4, while column 1 contains 1 and 2; discuss why row 2, column 1 must be 3.
- Independent or partner task (8–10 minutes): complete the grid. Ask partners to explain a move before writing it.
- Discuss (3–5 minutes): compare reasoning and check every row, column and box.
Student task
Fill each empty square with 1, 2, 3 or 4. Each number must appear once in every row, every column and each outlined 2×2 box.
| 1 | □ | □ | 4 |
| □ | 4 | 1 | □ |
| 2 | □ | 4 | □ |
| □ | 3 | □ | 1 |
Finish the sentence: “I placed ___ in row ___, column ___ because ___.”
Support and extension
Support: give four numbered counters and work on one row at a time; read instructions aloud. Extension: ask pupils to identify a square that can be justified in two ways, or compare a row-based explanation with a box-based explanation. Speed is not the goal.
Teacher answer key — keep separate until discussion
| 1 | 2 | 3 | 4 |
| 3 | 4 | 1 | 2 |
| 2 | 1 | 4 | 3 |
| 4 | 3 | 2 | 1 |
The fixed example has exactly one solution, checked by enumeration. This does not claim a particular difficulty rating.
Check for understanding
Success check: the pupil completes the grid consistently and explains at least one placement using the rules. If a number repeats, ask which row, column or box needs checking; do not treat a single error as a diagnosis of ability.
Create another version (optional)
Teachers can use the 4×4 Sudoku worksheet generator to prepare additional grids and answer keys. Review each new task before teaching. The linked service has free tools and optional paid features; the lesson above works independently.
Drafting support: AI. The fixed puzzle and answer were checked for internal consistency; this lesson has not been classroom-trialled. Contributor affiliation: PuzzleGenerator.