The Simmons family bought 9 bags of cookies. Each bag had 17 cookies. They have since eaten 25 of the cookies. How many cookies do they have left?

The Simmons family initially had a total of 9 bags * 17 cookies/bag = <<9*17=153>>153 cookies.

They now have 153 cookies - 25 cookies = <<153-25=128>>128 cookies remaining. Answer: \boxed{128}.