Save guides, add subjects and pick up where you ... between the desert and the mountain top is 42 °C. To subtract -2 from 4, start at number 4 on a number line, and count to the right.

To add -4 and 5, draw the starting number on a number line and count to the right when adding numbers. What is the difference in temperature between a desert at 40 °C and a mountain top at -2 °C?