Re: Do this in your head
 

Same here.

Re: Do this in your head
 

yeah got 4100 the first time. try keeping the 1000's apart then add the smaller numbers. you get 5000 by mixing up their places and what not.

Re: Do this in your head
 

Oops... you found what I did. Remember kids, 90 + 10 != 1000. ;)

Re: Do this in your head
 

I got 4100 first!!! =D Man I rule. :cool:

Re: Do this in your head
 

did it in my head and got 4100...

Really not that hard, but its a good way to confused others...

Re: Do this in your head
 

I got 4100 my first time, but I spend nearly a week trying to figure this out when I first saw it.

Re: Do this in your head
 

I got 4100.

I had the exact same problem on my precalc exam, got 5000, and got it wrong. Ive learned to add since then.

Re: Do this in your head
 

yeah quite a good question to test peoples ability of adding. obviousely alot of us cannot add yet we build successful robots. Makes you wonder sometimes how that works out :)