Ok, I know it's way past due, but I just updated my phone to the 7.0 nougat update. And I have no numbers in my calculator. They are ghost numbers on a white background and barely visible. I use my calculator a lot. Any suggestions?
Restart the phone. If that doesn't work, either reset to factory settings or download a calculator app from the Play Store.
The default calculator application might also have an update in the Play Store too.
