When a number is decreased by 10% of itself, the result is 36. What is the number?

If a number is decreased by 10%, that means that only 90% of the original number remains.

90% in decimal form is 0.90, allowing us to make an equation with a variable.

Let's make a variable called 'n' that represents the number.

0.90n = 36
n = 36/0.90
n = 40

The original number is 40.