The planet Venus has a mass of 4.869 ∙ 1024 kilograms. Use scientific notation to express the planet's mass in milligrams. 1 kilogram = 1,000,000 milligrams

To do this you need to multiple 1,024 by 1,000,000 to get 1,024,000,000 and then convert it to scientific notation. For that you need to know how many places there are after the first number. In this case it is 9. This will be 1.024 x 10^9. You have to remember that it is to the power of however many numbers are after the first. So even though we show 3 digits after the. we still have to include those in the power.