No one has gotten it yet. I knew people would be using a program to solve this, which makes this problem very very easy to solve if you can program. There is a simple (no need for any advanced math) mathematical way to solving this. In fact, this problem was taken from a mathematics competition I participated in where no calculators were allowed (only pencil/paper). 25 questions in 75 min --> 1 question per 3 minutes.
yeah the process of finding the sum might be easy, but the hard part is finding that process. what level math are you in anyway Zer0?
psh, I failed that competition, made too many stupid mistakes and ran out of time >.< lol, that's true, I think my method is kinda cool B) I'm in multivariable calc. But I don't think math level can really gauge how good a person is at math. You have to do competitions, otherwise you'll never see any difficult problems. Everything you learn in school is just applying formulas and techniques.
Ya, originally I thought he was asking for S(2008) so I thought, it was super easy. Then i realized he was asking for the sum so when I was at school, I wrote a little program in C++ for 5 minutes, tried it out, and wala... Wow zer0, you did math competitions? I did programming competitions in high school and I agree that competitions is the place where the truly bright people shine.
Wow, that's actually what I said except I typo-ed. XD I meant to say 54, not 44. Too bad you already guessed D:
Alas, Zer0's new rule. I think he should make an exception to this question, though, because it was so hard.
Dang, I totally didn't see that. Sorry to all who wanted to answer twice. Just negate my answer to make it fair.
I'm sure its okay. Zer0 will probably just cancel the question and move on. Or make an exception. Who knows, but good work!
hehe, I like how Cheeto and I have completely dominated the posting in this thread. And yeah, I don't think it really matters. I just wanted to find out if the program I wrote was correct, and since all 3 of us got the same answer, it probably was. Now I just wanna know Zer0's method of doing this without any computer aid. :yup:
omg sorry for the double post but i figured out how to do it by hand!!! i kind of grouped them by 10s and found the sum, then hundreds... then thousands.... i don't think i can explain it very well. *hears the sound of no one caring*
BECAUSE YOU N00BZ0RS CAN'T FOLLOW DIRECTIONS, THIS QUIZ AND CELEBRATION HAS BEEN CANCELLED! YOU ALL FAIL! j/k, its fine I'll give a point to anyone that PMs me their code to their program or some alternative way for solving the problem This question wasn't a part of the original semi-"official" list, but I thought it'd be fun to have a hard math question here. I do programming competitions too. Along with physics competitions and a lot of other competitions My method for solving the problem goes as follows: So the question asks for T = S(1) + S(2) + ... + S(2008) I basically sum up each of the decimal places separately (so sum up the thousands place, then hundreds, then tens, then ones) There are 3 possible values for the thousands place: 0, 1, 2 Obviously, you don't need to worry about the 0 case. There are exactly 1000 numbers where the thousands place is 1, so 1000*1 to you're total There are 9 numbers where the thousands place is 2, so add 9*2 to you're total For the hundreds place, you can have 0, 1, 2, ..., 9 If you think about it, you are adding up the sequence of numbers 200 times (ignoring the 0s). So basically its 200*(1+2+...+9) Same thing for tens place as hundreds place Same thing for ones place. For ones place however, you have to add 1+2+...+8 for when the thousands place is 2. You get 28054 as you're final answer