Here's how to convert four one-thousandths to scientific notation:

1. Convert to a decimal:

* Four one-thousandths is the same as 0.004

2. Move the decimal:

* To get a number between 1 and 10, move the decimal three places to the right: 4.0

3. Exponent:

* Since you moved the decimal three places to the right, the exponent will be -3.

4. Scientific Notation:

* The final answer is 4.0 x 10^-3