diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/20.n2/textbook.en.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/20.n2/textbook.en.md
index 18a7c7033..1c7ae0afe 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/20.n2/textbook.en.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/20.n2/textbook.en.md
@@ -3,8 +3,32 @@ title: Brainstorming on the mathematical tools required at each level
 published: true
 routable: true
 visible: false
+lessons:
+    - slug: define-g12-mathematical-tools
+      order: 3
+    - slug: define-234-mathematical-tools
+      order: 1
 ---
 
-#### Brainstorming on the mathematical tools required at level 2
+#### Define the mathematical tools required at level 2
 
---------------------------------
\ No newline at end of file
+--------------------------------
+
+with a **first classification to order the brainstorming a little** (counting, geometry, etc.).   
+It *does not presage chapter titles *.
+
+Feel free to create a new classification if necessary.
+
+
+! *xxx*
+!
+
+(XXX-YY)
+...
+
+--------------
+
+(XXX-YY)
+...
+
+-------------- 
\ No newline at end of file