999

[ETan]

PROBLEM.

The number 11 can be represented using exactly three 9's as 11=99/9.

Amazingly, the number 20 can also be expressed using exactly three 9's and elementary arithmetic signs.

What is this expression?

 

[azztec]

99/9+9=....20

 

[SackOfAllTrades]

that's not exactly three 9s, but it does work

 

[azztec]

oops, my brain didnt want me to read the part about 3 nines

 

[polotek147]

What class is that for? Seems like a cool class, really makes you pick your brain out.

 

[arcain]

9+9+sqrt(9) = 18+3 = 21

Doh.. thought that said 21! <slaps forehead>

hrmm.. must be time to go to sleep.

 

[AgentofEvil]

EDIT
Hey, wait that's wrong.

 

[azztec]

at least mine added up to 20

 

[polotek147]

So, you only have to use 9's, or can you use other #'s too? Don't mind me, my brained is pretty fried right now from the late night coding.

 

[ETan]

guess i'm not the only that's stumped by this question. It's actually part of a "Problem of the Week" that the math dept hosts. I like the idea. Prize kinda sucks though... at the end of semester, winner gets $20. Not great, but it's fun, and rewarding if u win. Or loose.

AFAIK only 3 9's are allowed, no other numbers. I pretty much picked the whole thing apart yet still no answer.

Wish i could use 4 9's...

 

[serialb]

<<at the end of semester, winner gets $20. Not great, but it's fun, and rewarding if u win. Or loose>>

Aren't you cheating now?

serialb

 

Flip 999 around 180 degrees.
You get 666. 😉

 

[bolomite]

(9+9)/.9 = 20

 

[woodly6]

Damn your good!

 

[johneetrash]

<< (9+9)/.9 = 20 >>



good stuff 🙂

 

[thereds]

But .9 isn't 9

 

[bandXtrb]

1 + 1 = 2

 

[thereds]

<< 1 + 1 = 2 >>



I forsee you working at NASA.

 

[Oalex]

<< But .9 isn't 9 >>



is a decimal point an elementary arithmetic sign?

 

[brada55378]

abcedef? g? 🙂 Humor is the best thing in life, especially directed at others. haha. 🙂