Okay. So basically, the numbers are in scientific notation. They are in powers of 10 and there are charts on powers of ten online. What we have to do is convert it into it’s long form, and then do what we need to do. Here are the answers in case you’re not sure.
15. 77,700,000
16. 955,300
17. 371,200,000
18. 19,430,000,000
19. 6.5
20. 820