Teacher gave that as a problem of the week, and from what I've done I figured it was unsolvable. Kind of messed up POW if it doesn't even work...

This is tough one bud. I know someone that are always playing Sudoku but they are at work right now. When this person comes back, I'll get them to give it a shot.

]]>3 + 0 + 0 + 8 + 2 = 13

]]>I asked this problem long time back when I was young.

Oh really? Actually I heard this problem from my friend.

]]>I only found 13 solutions to your alternative puzzle.

A unique solution exists with the constraint, "The value of the sum's first letter ('D') is a prime number".

Another alternative puzzle, ALPHA - BETA - GAMMA = DELTA, has 4 solutions. A unique solution exists with the constraint, "The value of the sum's first letter ('D') is an odd prime number".

]]>Welcome to the forum.

There is an entire "family" of straight lines where 7x+ 11y = something.

They are all parallel and as N gets bigger the lines move away from the origin. Joining (11,0) to (0,7) will produce one. What is N for this case?

That should give you a starting point.

Bob

]]>Tommy opens his bottle and begins drinking the soda. But when I open my bottle, it was frozen solid. I complained.

What happened?

]]>You've posted this as an exercise, but you've made it seem more like a help me problem. There's a difference: If it's an exercise, then members have a go for fun and maybe just post an answer. If it's a help me, then much more explanation would be provided and the 'student' encouraged to do some / most of the working themselves. Please clarify.

Bob

]]>Of course, I could be wrong... but it's a place to start. Let me know if you find it.. I will be unlikely to get to Beijing again to try it.

]]>its cool but just a bit confusing at first.

I was wondering if I should put some explanatory text or something showing how to play. thank you very much for your feedback

]]>ONE:

400:

169,196,961:

9+0:

9-8:

10-9:

81-0:

6^0, 8^0, 9^0, 10^0:

6/6:

8/8:

9/9:

computer runs at about 140,000,000 steps/second, that would take something like 10^18 years. However the constraints reduce this dramatically, so that the whole process only took 470 seconds !

I just use visual basic in Excel, so lower level languages like C++ would no doubt be even faster. The trick is to pick your blank cell loops so that you can use a 30ish cell sum constraint as soon as possible.

I first came across this type of puzzle in a Sudoku forum that I am in, where someone could not solve one of these problems with the first and last rows being completely specified (in addition to the nine 30ish cells).

Well I just love a programming challenge and I looped through the 28 unspecified cells, and found the unique solution in less than perceptible time.

To find other similar puzzles I just did a google search and eventually found this thread, which naturally suggested the 40 blank cell problem which obviously would have multiple solutions.

]]>