The total days of schooling in our family really depends on how many hours a day we do school and how much time we choose to take off. We do some school every day of the week. This is our first year in Wisconsin and I plan on 1-2 weeks off every 5-6 weeks, basically 1 week off mid season, 2 weeks off at season's change, but since this is our first year I cannot be sure how it will end up. On paper it would look like this:
52 weeks a year - 12 weeks off (spread out over the year) = 40 weeks
875 hours required / 40 weeks = 22 hours per week (rounded up)
22 hours per week / 5 days a week = 4.4 hours per day
We usually do 5 days at 3.5-4.5 hours and 2 days at 1.5-2.5 hours, with shortened "full" days resulting in longer "short" days (does that make sense?), that gives a weekly total of 20.5-27.5 hours on any given week. I aim for 25 hours a week and adjust each day as needed to get there. However at 25 hours a week we will be done in 35 weeks.
35 weeks x 7 days a week = 245 days of school
365 days a year - 245 days of school = 120 days, about 17 weeks, off.
That is way more time off then I plan on taking, I plan to stick to the schedule I mentioned above which would result in 1,000 hours total for the year (40 weeks x 25 hours a week = 1,000 hours a year). So I have no concern that we will have a problem meeting the required hours in the time frame given. We will most certainly go over and beyond the hours and subjects required by the state. Also just cause we take a week, or two, off doesn't mean we won't be doing any learning during that time it will just be a little less formal and possibly cover something unrelated to our current regular studies.
Bottom line is we will meet out required hours in 245 days (25 hours a week x 35 weeks, at 7 days a week), but will go at least another 5 weeks beyond that to surpass the required hours. Of course all this may change come spring and then again in the fall and again and again and again! It really depends on what works for us when, as is true for all homeschoolers I think but this is what I am planning on right now as it seems to be a good fit for our family.
I think I answered you question, if not let me know.
Also I didn't respond sooner because I have not been on Mothering in a very long time (over a year I think), my first day back on the message boards was the same day that I first responded to OP.