diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/10.n1/10.brainstorming/01.p1/textbook.fr.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/10.n1/10.brainstorming/01.p1/textbook.fr.md
index 4a6f38a6f..6a9b27d5d 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/10.n1/10.brainstorming/01.p1/textbook.fr.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/10.math-tools/10.n1/10.brainstorming/01.p1/textbook.fr.md
@@ -107,7 +107,9 @@ RÉAGIR :
 -  *Eléments, caractériser* des éléments
 -  *Elements indiscernables ou distincts*
 -  *Ensembles et sous ensembles*.
--  *Union $`\cup`$ et intersection $`\cap`$*
+-  *l'ensemble vide $`\varnothing`$
+-  *Union $`\cup`$,  et intersection $`\cap`$*
+-  *Appartenance $`\in`$ et non appartenance $`\not\subset`$
   
 RÉAGIR :
 ...  (XXX-YY)