8809 = 6
7111 = 0
2172 = 0
6666 = 4
1111 = 0
3213 = 0
7662 = 2
9313 = 1
0000 = 4
2222 = 0
3333 = 0
5555 = 0
8193 = 3
8096 = 5
1012 = 1
7777 = 0
9999 = 4
7756 = 1
6855 = 3
9881 = 5
5351 = 0
2581 = ?
Whats the last one equal?
And why?
At one time, I would have worked on this for as long as it took, then determine the answer - sans a computer. Today, the best I can do is rule out a 7, 8 or 9, then guessing at a 2. Let's see how well I did as I read the subsequent posts.
EDIT: Looks like my guess of 2 is correct, albeit I couldn't explain it, but my mind kept registering a two. Again, giving time I would have came up with it and been able to explain the process for its determination.
Thanks for allowing me to relive the days when I taught myself calculus (though it doesn't apply here), for it wasn't offered in high school where I attended. And yes, I truly did ace the math section on my SAT, taken at IU in Bloomington, IN. Plus, I was the first to finish the test.
Afterward, dad and I went fishing at Brown County State Park, where I practiced String in Tree Theory and Knot Untanglement.