Let have a Test:
You need to make a calculation. Please do neither use a calculator nor a paper. Calculate everything “in your brain”.
and add 40.
Now, add another 1000.
Now add 30.
Now, add 1000 again.
And add 1000 again.
And an additional 10.
So, You Got The RESULT! Be Quick! And Click here to check your result.
Quicker you see your result, sharper you are!
Do you think the result is 5000?
Actually, it is not. The correct result is 4100.