PRACTISE · EXPLAIN · TRY AGAIN
Three puzzles to think through together
A correct answer is a starting point. These worked examples help a learner explain why an answer works before moving into Piko Game’s logic challenges.
Explore the learning library
Seven worked guides: three logic puzzles, counting, making ten, fractions and a town-shop example.
Choose by the skill, then by the level
If a child can recognise numbers 1–4, try the Sudoku example. If they can follow arrows, try the robot route. Use the water puzzle when they are comfortable subtracting small numbers. These are practical starting suggestions, not an age test or a school assessment.
Read one example together, let the learner attempt it, then ask them to explain a move. In Logic Lab, choose Number Vault (Sudoku), Piko Pathfinder (robot routes) or Water Lab, and the first difficulty level. Read the opening tutorial, then select “Got it! Let’s play” to begin. Guest practice is available without signing in. Game sessions have a five-minute limit; the examples on this page have no timer.
Read the complete worked example →
1. Sudoku: rule out a number
In a 4 × 4 Sudoku, each row, column and 2 × 2 box contains 1, 2, 3 and 4 once. Here is a small part of a puzzle, rather than a complete board.
Question: A row reads 1 · blank · 3 · blank. The column through the first blank already contains a 4. Which number belongs in the first blank?
Show the answer and reasoning
The row is missing 2 and 4. The first blank cannot be 4 because its column already has a 4. Therefore it is 2, and the last blank in the row is 4. On a full board, also check the 2 × 2 box before placing a number.
When a learner gets stuck: Ask “Which numbers are missing?” before asking for an answer. Guessing a missing number without checking its column is the mistake this example targets. Next time, ask the learner to point to the clue that rules a number out.
Read the complete worked example →
2. Robot route: plan around an obstacle
Draw a 3 × 3 grid. Count rows from top to bottom and columns from left to right. Place the robot at row 1, column 1, the goal at row 3, column 3 and a rock at row 2, column 2. A move goes one square up, right, down or left. Diagonal moves are not allowed.
Question: Can the robot reach the goal in four moves without touching the rock? Write the arrows before tracing the route.
Show a route and explain its length
→ → ↓ ↓ travels along the top row and then down the right edge. It never enters the centre square. ↓ ↓ → → is another valid route. The goal is two columns right and two rows down from the start, so at least four moves are needed; these routes achieve that minimum.
When a learner gets stuck: Trace one arrow at a time with a finger. The sequence → ↓ → ↓ touches the rock on its second move. Reaching the correct final square is not enough: every intermediate square must also be valid. In the game, check its displayed board and move limit because they can differ from this example.
Read the complete worked example →
3. Water puzzle: record both containers
You have an empty 3-litre container A and an empty 5-litre container B. You may fill a container, empty it, or pour between them until the source is empty or the destination is full. There are no measuring marks. The goal is to leave exactly 4 litres in B.
| Move | A: 3 L | B: 5 L |
|---|---|---|
| Start empty | 0 | 0 |
| 1. Fill B | 0 | 5 |
| 2. Pour B into A | 3 | 2 |
| 3. Empty A | 0 | 2 |
| 4. Pour B into A | 2 | 0 |
| 5. Fill B | 2 | 5 |
| 6. Pour B into A | 3 | 4 |
The last pour transfers only 1 litre because A already holds 2 of its 3 litres. B therefore keeps 5 − 1 = 4 litres. A common mistake is to subtract A’s full capacity on every pour. Subtract only its remaining space, or the available water if that is smaller.
Try independently: Starting empty again, obtain 2 litres in B. Use the table to check your work after trying.
Check the shorter challenge
Fill B, then pour B into A. A holds 3 litres and B holds 2 litres: two moves.
Turn a round into useful practice
- Before playing, name one goal: rule out a number, plan a route or track quantities.
- After a mistake, identify the first move that broke a rule. Change that move before restarting.
- After success, explain the solution without copying it. Try a fresh round only when ready.
A game score describes that attempt; it does not establish mastery of a school curriculum. If a timed round feels rushed, return to these untimed examples. For school-year practice, use the country and school-year selector and choose a topic already familiar from class.
Choose a logic game →About this guide and corrections
Piko Game provides supplementary browser practice. This guide explains rules used by the site’s Sudoku, robot and water games using separate worked examples. It is not a textbook extract, a complete national curriculum or a claim of measured learning improvement.
Found a wrong answer or a game that does not load? A parent or teacher can send the page address, game name, language and the problem description to j565718319@gmail.com, the contact listed in our privacy notice. Please omit children’s names and account details from examples. Release notes describe published changes.