Update textbook.en.md

00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/30.n3/textbook.en.md

@@ -3,8 +3,30 @@ title: Brainstorming on the mathematical tools required at each level
 published: true
 routable: true
 visible: false
+lessons:
+    - slug: define-234-mathematical-tools
+      order: 2
 ---
 
-#### Brainstorming on the mathematical tools required at level 3
+#### Define the mathematical tools required at level 3
 
 --------------------------------
+
+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)
+...
+
+--------------