Update Discrete_Mathematics_List.html

Author: toprise

Math/Discrete Mathematics/Discrete_Mathematics_List.html

@@ -195,6 +195,15 @@ <h1 class="page-title">Math Notes</h1>
             </a>
         </article>
 
+        <article class="knowledge-card">
+            <a href="3.html" class="card-link">
+                <div class="card-content">
+                    <div class="card-icon">📚</div>
+                    <span class="card-text">3. About the Operation of Proposition</span>
+                </div>
+            </a>
+        </article>
+        
         <article class="knowledge-card back-card">
             <a href="javascript:history.back()" class="card-link">
                 <div class="card-content">