Cute!
The easy way, of course, is to first add up the "thousands", then add up
the "tens".
It appears that the confusion results from generalization between hundreds
and thousands. The "90" is a discriminative stimulus for preparing to
increase the next decimal column by one. Since that column is vacant, one
goes to the next column (thousands) and bumps 4000 up to 5000, rather than
90 to 100. Experience solving problems doesn't always help!
>> >
>> > MATH RIDDLE --------- MUST BE DONE IN YOUR HEAD
>> > >
>> > >This riddle must be done IN YOUR HEAD and NOT
>> > >using paper and a pen.
>> > >Try it - it's weird
>> > >
Take 1000 and add 40 to it.
Now add another 1000.
Now add 30.
Another 1000.
Now add 20.
Now add another 1000.
Now add 10. What is the total?
>> > >
>> > >
>> > >
>> > >(Scroll down for the answer)
>> > >
>> > >Did you get 5000?
>> > >
>> > >
>> > >The correct answer is actually 4100. Don't believe it?
>> > >Check with your calculator! The brain sure knows how to play
>> > >little tricks on us, doesn't it?
* PAUL K. BRANDON [EMAIL PROTECTED] *
* Psychology Dept Minnesota State University, Mankato *
* 23 Armstrong Hall, Mankato, MN 56001 ph 507-389-6217 *
* http://www.mankato.msus.edu/dept/psych/welcome.html *
