diff --git a/education/software development/ECE1400/Chapter 4 Exercises.md b/education/software development/ECE1400/Chapter 4 Exercises.md
index d76aac6..8090369 100644
--- a/education/software development/ECE1400/Chapter 4 Exercises.md	
+++ b/education/software development/ECE1400/Chapter 4 Exercises.md	
@@ -9,7 +9,8 @@ b. `-1`, `-2`
 c. `-1`, `-1`
 d. `1`, `2`
 # 9.
-a. 
+a. `63 8`
+b. ``
 
 # 11.
 # 15.