Since I want to go to the gym today, I need to go down 10 floors. Then, I want to visit my friend who lives on the tenth floor. So, I need to go up 6 floors to get to the tenth floor because 0+-10+6=-4. (4 floors below my floor)
It takes me a minute to walk 2 floors down. If I start at the twentieth floor, I would be on the eighteenth floor after a minute. That means 5 minutes later, I would be on the tenth floor because 20+(-2)5=10.
One day, it took me 15 minutes to walk down 100 feet. Next day it took me 12 minutes to walk down 84 feet. I walked faster the second day because the first day, I walked at a rate of 6 2/3 feet per minute and 100 divided by 15= 6.6 repeating. The second day, I walked at a rate of 7 feet per minute because 84 divided by 12=7. 6 2/3<7.
I wanted to get some exercise today so I walked up and down some steps. First, I walked from my floor up to the nineteenth floor, then down 15 floors to the fourth. In total, I walked up and down 20 floors since 0+|5|+|-15|=|20|.
If I wanted to get on my roof, I would travel 7 floors up. That's because the roof is one floor above floor 20 and 14+7=21. However, if I wanted to go from the first floor to the top floor which is 20, I would go 19 floors up because 20-1=19.
Today, I'm going to the gym, then going to go to the laundry room. The gym is on the fourth and the laundry room is on the nineteenth floor. I'm going to travel a total of 25 floors because 0+|-10|+|15|=|25|.