If today is Thursday, what day of the week was it 1000 days ago

1000 days is 142 weeks and 6 days.

That is, exactly 143 weeks ago, but add 1 day.
So, Friday

To find out the day of the week 1000 days ago from today, you need to divide 1000 by 7 (the number of days in a week) to determine how many full weeks are included in those 1000 days.

1000 ÷ 7 = 142 remainder 6

This means that there are 142 full weeks in 1000 days, with a remainder of 6 days.

Now, starting from today (Thursday), you need to go back 6 days. Here's how you can do it:

Thursday (today) ➜ Wednesday ➜ Tuesday ➜ Monday ➜ Sunday ➜ Saturday ➜ Friday

So, 1000 days ago from today (Thursday) was a Friday.