diff --git a/UNB/Year 4/Semester 2/CS3873/2024-02-12.md b/UNB/Year 4/Semester 2/CS3873/2024-02-12.md
index 65a2214..37f316f 100644
--- a/UNB/Year 4/Semester 2/CS3873/2024-02-12.md	
+++ b/UNB/Year 4/Semester 2/CS3873/2024-02-12.md	
@@ -1,2 +1,4 @@
 Lecture Topic: UDP and Reliable Data Transfer
 
+Uses 1's compliment sum to do check-summing (info in slides)
+