You have 1000 maths puzzle

You have 1000 maths puzzle

Make this without a calculator or paper.
Just your mind.

You have 1000,
add 40,
add 1000,
add 30
add again 1000,
add 20,
add again 1000,
and finally add 10.

What is the result ?

Click here for Answer

The result is 4100.