(My main focus will be on unit 3.18)

College Board Notes Undecidable Problems

Decidable problems: Yes/no answer for any given input. Output is always correct.
Undecidable problem: No algorithm can be made which is always able to have a correct output of yes/no
- Halting problem: Given an arbitrary computer program with given inputs, will the program stop of will it run forever?
- No way to solve with yes/no answer all the time
- Ex of Halting Problem: Website take too logn to load. Computer stops programs after certain amount of time

Youtube Video Notes(Link)

Machine to diagnose whether a code runs forever or not is logically impossible
If combined into one huge machine, a negator can reverse the output of machine which diagnoses a halt
- Since negator contradicts that machine, it shows that the entire computer is not correct, so it’s not always accurate. This is an undecidable problem shown by the Halting Problem.

Khan Academy explains the same thing as the Youtube Video. The flow chart is very good, could possibly be used for teaching.
Computers cannot tell if a program runs forever, if loop takes too long, the code terminates

Use Khan Academy flow chart or make one similar to it.
Expect people to get very confused at first. Try your best to explaining things better and teach it one step at a time
To teach it one step at a time, first demonstrate a forever running code. You can do this through an integer test but you add 1 everytime, so computer runs forever
For decidable problem, just do a simple math program. Almost anything works for undecidable problem
For hacks, try doing something related to undecidable problems that doesn’t involve any code, since it’s too complex to use much code.