How do I calculate (today) - (date)?

How do I calculate (today) - (date)?

I'm trying to create a formula which tells me how long I have items on-hand. I think I've gotten close, but I can't get it to work. When I use ( zoho.currentdate - input.MFR_DELIVERED) I get a long version of time. I can't seem to figure out the rest to get the short for of the time. For example, instead of just "9" (for days on hand), I get 777600000. And, I can get this " /(1000*60*60*24)" to work in excel, I just don't know Zoho language to make it work here.