Mars' atmosphere is about a hundred times thinner than Earth's. With its extremely thin atmosphere, Mars cannot retain heat from the Sun and thus experiences extreme swings in temperature, even between day and night. The temperature in the same spot at its equator can be around 20°C in the day only to drop drastically to −50°C at night.
🔥❄️ What is the difference between these two temperatures?
Difference = 20°C − (−50°C) = 70°C.
A swing of 70 degrees Celsius between day and night — far more extreme than anywhere on Earth. To compute "subtract a negative number" you need integer subtraction, which is what Section 2.2 teaches.
In this chapter, we will learn to:
make sense of negative numbers and their application in real life;
represent positive and negative numbers on a number line;
perform the four operations on integers;
identify rational, irrational and real numbers; and
perform the four operations on real numbers, including with the use of calculators.