my phone number is unknown-- how do i find it
Welcome to Android Central. You did not specify which device you have, but on my Note 4, I go to Settings > General > About Device > Status > scroll down to "My Phone Number".
I hope this will be of help to you. If you still have issues, please create an Android Central account (it's free) and reply in this thread so you can receive further assistance. It would be helpful if you indicated which device you are using.
Posted via the Android Central App on my Note 4