You multiply all of the digits on the bottom starting from right to left with the numbers on the top (Biggest number on top smallest on bottom). after you multiplied 5000 by the first zero in 2000 you go down a line (Lined paper is the best to use) and add a zero as a place holder and then multiply 5000 by the second zero in 2000 then after that you go down a nother line and add two zeros for a place holder... you repeat the steps of multiplying and go down another line and add three zeros as place holders. after your finnished multiplying you add all the numbers in your lines together and you will get 10,000,000
60 miles per hour and 55 miles per hour it will be 240 miles over 4 hours because if you divide 240 by 4 it is 60 miles faster than the other which is 55 miles per hour.