I don't know about that one. 4!! is 8, 8!!!! is 32. 32*24+4 is 772, and /4 is 193? Can we use 0 like that? I'm just gonna propose 71 = (4!+4.4)/.4 72 = (4!+4)/.4+sqrt(4) Now I'm having trouble getting 73. If I can't get anything with 4!, .4, etc. I'll try nPr and nCr. Someone else can try to beat me to it though.
I think anything should be possible with the rules we've opened up. Worst case we can resort to concatenation? 73 = (4!!)!/(4!!)!!-(4!!)*4
Yeah, that's kind of the reason why I used it, noone seemed to be able to get it working properly, so I did it more cheety style Also, my calculator gives ERROR: Overflow on your solution... I now just have to trust you... This was my original: wrong number... 70 = 4*4! - 4! - Sqrt(4) HHere is another cheety one: I need to start learning for my Economeny test later today... ((4^2)^2 +44)/4
It's probably doing a factorial of a factorial, instead of a 'double factorial'. http://mathworld.wolfram.com/DoubleFactorial.html 8! = 8*7*6*5*4*3*2*1 8!! = 8*6*4*2 8!!! = 8*5*2 ...and so on (4!!)!/(4!!)!!-(4!!)*4 =8!/8!!-8*4 =40320/384-32 =73 edit: Also, I learned about it after seeing this, to give credit where it's due
Huh, I didn't know about that. Interesting. This is hard... What are you guys' strategies? Have you made a document somewhere, or do you always figure things out from scratch?