Add why_we_use_types_exercise1.py with type behavior demonstration

- Create exercise file demonstrating why type hints matter
- Include half(), double(), and second() functions
- Add example showing string multiplication vs numeric multiplication
- Document expected behavior: double("22") returns "2222" due to string repetition
- Include question and answer explaining the type-dependent behavior

Author: Iswanna

prep/why_we_use_types_exercise1.py

@@ -0,0 +1,20 @@
+def half(value):
+    return value / 2 
+
+def double(value):
+    return value * 2 
+
+def second(value):
+    return value[1]
+
+
+print(double("22"))
+
+# Question
+# Predict what double("22") will do. Then run the code and check. Did it do what you expected? Why did it return the value it did?
+
+# Answer
+# The function double("22") will return "2222".
+# When I ran the program, it returned what I expected.
+# The return value is "2222" because the argument is a string, so the * operator duplicates the string instead of 
+# multiplying a number. Python repeats the string twice: "22" + "22" = "2222".