Question

The gold leaf on your necklace is 0.000045 of an inch thick. How do you write 0.000045 in scientific notation?

Answer 1

The answer would be 4.5 × $10^{-5}$

Answer 2

Move the decimal the required number of spaces to the right til you get a number between 1 and 10. You have to move the decimal 5 places to the right to get 4.5  Because you started out with a number less than 1, the exponent is negative.  This would be written 4.5 x 10^-5