Here's how to get there:

1. Move the decimal point: Start at the decimal point and move it to the right until you have a number between 1 and 10 (in this case, 8.18).

2. Count the moves: You moved the decimal point four places to the right.

3. Exponent: Since you moved the decimal to the *right*, the exponent will be negative. The exponent is the number of places you moved the decimal, so it's -4.

Therefore, 0.000818 in scientific notation is 8.18 x 10⁻⁴.