You have probably worked through advanced calculus, differential equations, state space equations, and vector algebra, but let?s see if you can do some elementary math.

Note: This calculation must be done in your head only and not using paper and pen.


Try it:


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 answer.































































Did you get 5000? Well, the correct answer is actually 4100. Don't believe it? Check with your calculator. The decimal sequence confuses our brain, which always jumps to the highest decimals (100s instead of 10s).