Write each number in scientific notation 0.00000000850

This is going to be a negative exponent, because it's less than 1. move the decimal to where the non zero number is more than 1 but less than 10.

8.50 is more than 1 but less than 10, now write that time a power of 10.

X10^-9

so together it's: 8.50X10^-9