Question

the common cold virus has a diameter of about 0.000000028 of a meter. Express this in scientific notation.

Answer 1

So scientific notation is bring a number to it's last digit that's greater then zero, meaning for example 0.0000045→4.5 and multiplying it by a power of 10 to get a condensed version of the original number.  

So in this case you'd get 2.8*10^-8