Åk 6–9
2.1 Experiencing Negative Numbers
In the beginning of this section, we showed different situations where you could come into contact with negative numbers.  We will looks a bit more at these examples and give you some questions to think about:
  • Temperature
    If the temperature is -4ºC on a winter day, and the temperature lowers by 3ºC, in other words, it becomes 3ºC colder, how cold then is it?  Which of these two temperatures would you call the coldest?
  • Money
    If you loan 150,000 kr from the bank for a car, you owe the bank 150,000 kr, or that you have a balance in the bank of -150,000 kr.  If you loan another 70,000 kr, what is your balance with the bank?
  • Riding in an Elevator
    Imagine that you are standing in an elevator which has the buttons -2, -1, 0, 1, 2, 3, 4 (0 normally represents the lobby).  What do the buttons -2 and -1 really mean? Which is the lowest floor?
  • Sea Level
    The surface of the Dead Sea is 392 m under what we call sea level.  Because sea level is 0 m, we write this as -392 m.  Parts of the Netherlands lay also under sea level and the lowest point lies 6.7 m under sea level, in other words 6.7 m.  Which is closest to sea level, the Netherlands or the surface of the Dead Sea?  Which of the numbers -6, 7, and -392 is the largest and which is the smallest?
  • Time Zones
    If Chile has GMT (Greenwich Mean Time) –5 hours and the times is 12:00 in Greenwich. Is the time more or less in Chile? What is the time in Chile?