2.0x10^-5 or 2.0E-5 —this is because as a small decimal number, you move the decimal to the right five spaces and then add a negative to the decimal to indicate that when you translate back (from scientific notation to 0.00002) you will move the decimal to the left
8 and .25 are rational numbers because integers are negative and whole numbers don't include decimals and rational numbers can include whole number like 8 or 8/1 and .25.