The first one is 200,000 divided by 10. The answer is 20,000.
For the second one, the tenths place is the one just on the right side of the decimal. Find the number right before it. If the number is 5 or higher, then you round up. It's 5, so round up, and get rid of the 2 at the end. Since you round up to 10, not 0, you need to add a 1 to the 8. Your answer should be 78.9