Liz had attended class every day since she started kindergartener. she said she had been in school for about 1000 days. what could the actual number of school days be if she rounded to the nearest ten?

I am not too sure if I understand, but I take it that it means that she has started school 1000 days ago.

So we have to calculate the number of working days in the last 1000 days: we know that in every 7 days, 5 days are working days. (let's ignore the holidays for now... for this we need a more detailed information about when it was).

So to calculate this, we calculate:

so an actual number of days could be 714 or 715. If we round it, it's 710 (or 720 if it was 715 indeed)...