3. In 2002, Home Depot’s sales amounted to $58,200,000,000. In 2006, its sales were $90,800,000,000

a. Write Home Depot's 2002 sales and 2006 sales in scientific notation.

For $58,200,000,000., move the decimal point to the left until it is to the right of the first non-zero digit (5). Multiply by 10 raised to the power of the number of digits moved (10). So the answer is

5.82*1010

I will leave you to do the second one. Post your answer for checking if you wish.