Hide function and lock for specific cell and allowing editing to other cell

Dear Sir
would you please help me in hide and lock all function in attached file with (all RED cells).
and other cell editable (other color)
i can't attached file i didn't know why but my fucntion is
=IF(E287<=12,"25%",IF(E287=15,"32%",IF(E287=18,"38%",IF(E287=24,"50%"))))
in many cells
regards