4100 is the right answer.. but if asked orally, without having time to think, lots of people will have 5000 (as per TokyoJames' post)

 

Here is what I did:
1000+400 (instead of 40)
1400+1000
2400+300 (instead of 30)
2700+1000
3700+200 (instead of 20)
3900+1000
4900+100 (instead of 10)
You see, if you do it in your head, some people will think "1000+40= oh yes 1400" because of the 1000 is making you think that the 40 is 400.

 

I got 4100 also. I guess I should thank my mother for making me take abacus classes

 

4100 for my wife and me. I work with numbers in measurements, though.

 

LOL, I did what George did. The first time

 

yeah, i got 4100

 

4100...i just added all the thousands and hundreds...go figure

 

HELP! My brain is rotting!

....

I got 5000, and then when I saw the answer was 4100 I was flabberghasted and frantically scrolled down til I saw an explanation LOL