Updating Data based on fields

Updating Data based on fields

I am trying to get this to work. Keeps giving error. 
Need to update daily the number of days a home has been listed based on todays date and a date input on the form. Was trying to do it using a daily schedule, but also ok to do it with a buttom I will push every day... but can not get it to work. What am I doing wrong? Keep getting the "Improper Statement" error. 

for each Days in STR_house_estimates [  ]
{
Days.Days_on_market = ((zoho.currentdate - Days.Date_listed)) / (1000 * 60 * 60 * 24);