EXAMPLE 2 Using Integer Subtraction

Geography

The highest point in Asia is Mount Everest at 8850 meters. The shore of the Dead Sea, the lowest point in Asia, is about 410 meters below sea level. What is the difference between these elevations?

SOLUTION

STEP 1 Represent the two elevations with integers.

Mount Everest: 8850 m Dead Sea: –410 m

EXAMPLE 2

STEP 2 Find the difference of 8850 and –410 meters.

8850 – (–410) Rule for subtracting integers

= 9260

Answer

The difference between the elevations is 9260 meters.

Add.

= 8850 + 410

Using Integer Subtraction

EXAMPLE 3 Finding a Change in Temperature

Weather

In Fairfield, Montana, on December 24, 1924, the air temperature dropped a record amount. At noon, the temperature was 63oF. Twelve hours later, the temperature was –21oF. What was the change in temperature?

SOLUTION

Change in temperature = end temperature – start temperature

= –21 – 63 Substitute values.

EXAMPLE 3

= –21 + (–63) Rule for subtracting integers

= –84 Add.

ANSWER

The change in temperature was –84oF, so the temperature dropped 84oF.

Finding a Change in Temperature

GUIDED PRACTICE for Examples 2 and 3

ANSWER 543 ft

ANSWER 44oF

Elevation

Find the difference between an elevation of 535 feet above sea level and an elevation of 8 feet below sea level.

5.

Temperature

The temperature at 6 A.M. was – 12oF. At 3 P.M. the temperature was 32oF. What was the change in temperature?

6.