1.) 3.8 because 10^8 is 100,000,000. 8.4 times 100,000,000 is 840,000,000. Then, 2.2 times 1000,000,000 is 220,000,000. You divide those and get 3.8
2.) 111.111111 because 10^-4 is .001. you divide that by 9 and get .009. 10^-5 is .00001, you times that by 3.5 and get .000035 which is 111.111111
3.) 500
4.) 177.083333
5.) 30