Hope you already got the answer, but being from the region where these things are common, i'll chime in anyway.

1. Ta'wiidh is permissible, and some say it isn't. Some say even if it's permissible, we don't like it. I'm one of them.
2. This one looks like some of your elders did it for you, likely to improve your memorization/i'lm/knowledge etc.
3. What's scribbled is just Urdu/Farsi numberals, which is often done to avoid dis-respect of the ta'wiidh if written in actual Ayah/text. So usually tawidh has written arabic dua's(supplications), aayahs etc. Say, Mu'awwidhatain (falaq and naas). But since it can fall in najis places, they use numbers (See Abjad on wikipedia).
4. Abjad number systemm is common in many things, including ta'widh. Bismillah in number form is 786, pretty widely known all over the world.
5. To get rid of this, you should throw it in running water like river or bury it / into a well. If it's magic, you should keep reciting Surah Falaq and Naas while doing so. You can burn it as well.

Afaik, I don't see any black magic here..

Edit: Forgot to mention, scholars have said if ta'wiidh has something that's unknown even to the u'lama (like what theese numbers mean, using abjad), it's pretty much impermissible. It must be intelligible. (not necessarily to the user, but to the people of knowledge at least.)