Column B has formula:
I can also use =mid or =right and column B shows literally the formula not the result which should be 1511
Do you have your spreadsheet in formula mode? Press Ctrl + ` (left of the number 1 key) and see if that helps!
1. Make sure that the cell format not in 'Text' and should be 'General'.
2. If still you have problem, Press 'Ctrl + `'