Someone just trying to finish this stuff lol i don’t feel like working it out

Okay, so if a reading taken at the beginning of February read 19,423 and a reading taken at the end of February read 20,288, then the difference of those numbers would have been used during the month of February. So, 20,288-19,423=865. So, 865 kilowatt hours of electricity were used in February.
Same thing in March. So, if, at the beginning of March, the reading said 20,288 and, at the end of the month, the reading said 21,163, then 21,163-20,288=875. So 875 kilowatt hours of electricity were used in the month of March.
Question 5 says that Terry earned 19,436 dollars last year. But this year, he got a raise and earned 23,457 dollars. The difference between that would be 23,457-19,436=4,021. So, Terry earned 4,021 more dollars this year.
Then it asks you how much money would you earn if you got the same raise next year. So take your current yearly income, which is 23,457 dollars, and add 4,021 to that. This would be 27,478 dollars, which would be your answer.
Question 6 says that the Leibnitz Range on the Moon is 35,000 feet high. Mount Everest is 29,028 feet. How much higher is the Leibnitz Range than Mount Everest? You take the height of the Leibnitz Range, 35,000 feet, and subtract the height of Mount Everest, 29,028 feet. 35,000-29,028=5,972. So the Leibnitz Range is 5,972 feet higher than Mount Everest.

In this problem it decreased 20%