Scientific notation is a method used to represent large or very small numbers in an understandable way, for example we have 9.80*10^-3, which is actually 0.00980, but in a scientific notation the number is better represented. For our question we have this calculation:
9.80*10^-3 + 1.60*10^-4 = 9.96*10^-3, this will be the final answer