calculating number of days

calculating number of days

Sorry to be so ignorant on database forms and formulas, however,
I created this simple db and cant figure out how to calculate the number of days between dates entered.
we have level of care date 1  and level of care date 2  and so on.
I would like to have Days Level 1 to Level 2 calculate for me. I have included pic.

thank you for any assistance.