Excel's Least Common Multiple

[MonkeyF0cker]

Doesn't work very well for large numbers.

Put the following into an Excel spreadsheet:

A1: 1533939
A2: 178365
A3: 16215
A4: 1081
A5: 47

If you try performing LCM(A1:A5) to find the least common multiple, its output is: 273,600,851,370.

The actual LCM is 7,669,695 which can make a pretty significant difference when you're approaching data type constraints as you code. If you surpass the threshold of a data type (depending on whether the data type is signed or unsigned), it will flip like Frogger or Super Mario Bros. (either to 0 or a negative constraint) which may be fine (or desirable) when you're playing a video game, but not so much when you're dealing with dependent variables as part of larger calculations.

 

[Matty]

I get 7,669,695 in Excel 2010.

 

[RayRay]

i get 7,669,665 without using excel, computer or calculater...fingers and toes is as complex as i need to get...
back to tv i guess

 

[Matty]

Justin7 gets his LCMs directly from a Hungarian syndicate of Math PhD's. He pays them a mere 30k a year for the privilege.

 

[rito]

i get 7,669,695 on excel 2007 and excel 2011mac

 

[MonkeyF0cker]

Wow. Really?

Hmm. I get 273,600,851,370 in any Excel 2007 spreadsheet.

WTF. And here I was about to write an entire prime factorization algorithm...

 

[MonkeyF0cker]

I guess I might as well upgrade Office then...

 

[Tron]

Boys, what the fuck is going on here?

Is Excel just a complete mess or what?

Mr.M, get the entire Gamelive security team on a conference call RIGHT NOW. Shit is about to get real.

 

[MonkeyF0cker]

Ahh. I found the issue.

Try this.

Put this in each cell:

A1: =COMBIN(47, 5)
A2: =COMBIN(47, 4)
A3: =COMBIN(47, 3)
A4: =COMBIN(47, 2)
A5: =COMBIN(47, 1)

Now, do the LCM(A1:A5) and tell me what you get.

 

[MrMonkey]

Boys, what the fuck is going on here?

Is Excel just a complete mess or what?

Mr.M, get the entire Gamelive security team on a conference call RIGHT NOW. Shit is about to get real.

Sorry but all our manpower are still working on the upside !!!!!!!!!!! thing! Monkey-Fuker!!!!!!

 

[RayRay]

Boys, what the fuck is going on here?

Is Excel just a complete mess or what?

Mr.M, get the entire Gamelive security team on a conference call RIGHT NOW. Shit is about to get real.

nope, just MF i think...

Hey MF, why do you even bother with this shit? why dont you just buy a year long package from vegaskillers and sleep well at night knowing that you will continue to get the best picks available until you turn a profit

wake up buddy

 

[Matty]

Ahh. I found the issue.

Try this.

Put this in each cell:

A1: =COMBIN(47, 5)
A2: =COMBIN(47, 4)
A3: =COMBIN(47, 3)
A4: =COMBIN(47, 2)
A5: =COMBIN(47, 1)

Now, do the LCM(A1:A5) and tell me what you get.

Yeah, 273,600,851,370.

 

[rito]

Ahh. I found the issue.

Try this.

Put this in each cell:

A1: =COMBIN(47, 5)
A2: =COMBIN(47, 4)
A3: =COMBIN(47, 3)
A4: =COMBIN(47, 2)
A5: =COMBIN(47, 1)

Now, do the LCM(A1:A5) and tell me what you get.

273,600,851,370

 

[MonkeyF0cker]

Fucking weird.

I guess I need to report this to Microsoft.

 

[MonkeyF0cker]

Even if you copy/paste special with just the values, the LCM calc is wrong.

 

[Matty]

Even if you copy/paste special with just the values, the LCM calc is wrong.

Yap! And then, if you retype 1533939, 7,669,695 comes back.

 

[rito]

good work microsoft.

what on earth are you doing MF?

 

[MonkeyF0cker]

Nothing special really. Just trying to find a lowest common denominator so that I can find the union of (add together) several probabilities.