Free teaching guide · Grades 4–7 (ages 9–12)
Grid Mysteries
The Great Detectives · Special agent of logic
2 sessions of 45 minutes · 7 missions
Teacher’s guide
Learning goals
- Read precise clues and draw conclusions from them.
- Find your way on grids from 6×6 to 8×8.
- Reason by elimination and write up a justification.
- Make up a puzzle that works for a classmate.
Lesson plan
Session 1 · Agent training
- Mission 1: the rules of the game (page 3 of the book).
- Mission 2: the practice case, on the board.
- Mission 3: a first case from the file “The Middle School,” in pairs.
- Mission 4: write up your justification.
Session 2 · Seasoned agent
- Mission 5: the agent’s word search.
- Mission 6: the agent card.
- Mission 7: make up a 6×6 case for the class next door.
- To go further: follow the Shadow mystery, one file a week.
Tips and discussion ideas
- There is often more than one way to reason it out: have students compare their paths out loud.
- Every case in the book has a hint printed upside down at the bottom of the page; the solved grids start on page 95 and the step-by-step explanations on page 99.
Student pages
Your missions
Name: ______________________ Date: ______________
Mission 1The rules of the game
Read the rules together.
Mission 2The practice case
Follow the solution step by step.
Mission 3File 1: the middle school
Your turn, in pairs!
Mission 4Explain like a pro
Explain your reasoning: “I put … on … because ….” One line per token.
Mission 5The agent’s vocabulary
Find the 10 hidden words (across, down or diagonally).
| C | O | A | G | E | N | T | N | K | W | N |
| O | B | T | G | P | B | P | G | T | I | O |
| L | S | U | S | P | E | C | T | J | T | R |
| U | R | J | C | H | A | C | V | G | N | E |
| M | F | I | L | B | A | N | N | V | E | P |
| N | M | M | U | V | G | D | O | P | S | O |
| H | P | S | E | V | E | D | O | F | S | R |
| H | C | U | L | P | R | I | T | W | B | T |
| C | M | L | L | L | L | O | E | I | S | R |
| L | O | G | I | C | T | D | J | O | F | M |
| H | L | S | T | A | T | E | M | E | N | T |
- CULPRIT
- SUSPECT
- WITNESS
- SHADOW
- COLUMN
- REPORT
- AGENT
- CLUE
- LOGIC
- STATEMENT
Mission 6Your agent card
Just like in the book, fill in your agent card.
Great Detectives Squad
Agent name:
Age:
My strong point:
Mission 7Make up a 6×6 case
Draw the areas and the furniture, place 5 suspects and the object (one per row and per column), then write the clues. Test it on each other!
My clues:
1.
2.
3.
4.
5.
6.
The culprit:
Great Detective Certificate
This certificate is awarded to
who handled every case methodically, explained every deduction and unmasked the culprit!
Date ______ / ______ / ________ · Signature: ________________
For the teacher
Answer key
The answer key is waiting for you
Enter your email address to see it, print the guide and get it as a PDF. It’s free.
Mission 2The practice case
Follow the solution step by step.
Noah goes to C5, Jade to E3, Max to D4, Leo to A2, Sam to F1 and the logbook to B6: the logbook is in the cafeteria, and only Noah is there. He is the culprit!
Mission 3File 1: the middle school
Your turn, in pairs!
Zoe goes to B1, the watch to A4, Sam to E3, Leo to D2, Ivy to C6 and Jade to F5: the watch was in the schoolyard (square A4), and the culprit is Ivy. Step-by-step explanation on page 99 of the book.
Mission 5The agent’s vocabulary
Find the 10 hidden words (across, down or diagonally).
| C | O | A | G | E | N | T | N | K | W | N |
| O | B | T | G | P | B | P | G | T | I | O |
| L | S | U | S | P | E | C | T | J | T | R |
| U | R | J | C | H | A | C | V | G | N | E |
| M | F | I | L | B | A | N | N | V | E | P |
| N | M | M | U | V | G | D | O | P | S | O |
| H | P | S | E | V | E | D | O | F | S | R |
| H | C | U | L | P | R | I | T | W | B | T |
| C | M | L | L | L | L | O | E | I | S | R |
| L | O | G | I | C | T | D | J | O | F | M |
| H | L | S | T | A | T | E | M | E | N | T |
- CULPRIT
- SUSPECT
- WITNESS
- SHADOW
- COLUMN
- REPORT
- AGENT
- CLUE
- LOGIC
- STATEMENT