Use a number line to help represent the situation from the exercise. Recall how to describe changes on a number line using absolute values.
95 feet under the surface
Practice makes perfect
We want to find the present location of a deep-sea diver, relative to the surface. We can use a number line to help us visualize the given situation. From the exercise, we know that the diver dives 81 feet below the surface. Then he dives 14 more feet. Let's list the steps we will follow to create the number line for this situation.
First, we start at 0.
Then, we move 81 units to the left. This represents the diver's location after the first dive.
Finally, we move 14 units to the left. We do this to represent the second time the diver dives.
We will use a vertical number line to help us visualize the situation. Moving down the vertical line represents moving to the left on a horizontal number line. Keeping this in mind, let's mark these steps on the number line.
As we can see from the graph, the sum of - 81 and - 14 is located 14 units below - 81. We can add the two integers to find the diver's location. Let's take a look at the expression from the exercise.
-81+(-14)
Notice that we are adding two integers with the samesigns, both negative. Because of this, we will add the absolute values of the integers. Let's take a look.
Keep in mind that we moved two times to the left of 0 on the number line. Because of this, the sum is negative. We can say that the diver is 95 feet below the surface.
