Main Idea

Key Concept: Subtract Integers

Example 1: Subtract Positive Integers

Example 2: Subtract Positive Integers

Example 3: Subtract Negative Integers

Example 4: Subtract Negative Integers

Example 5: Evaluate an Expression

Example 6: Real-World Example

• Use the rules for subtracting integers.

Subtract Positive Integers

Find 2 – 15.

2 – 15 = 2 + (–15) To subtract 15, add –15.

= –13 Simplify.

Answer: –13

A. –15

B. –7

C. 7

D. 15

Find 4 – 11.

Find –13 – 8.

Subtract Positive Integers

–13 – 8 = –13 + (–8) To subtract 8, add –8.

= –21 Simplify.

Answer: –21

A. 24

B. 20

C. –20

D. –24

Find –22 – 2.

Subtract Negative Integers

Find 12 – (–6).

12 – (–6) = 12 + 6 To subtract –6, add 6.

= 18 Simplify.

Answer: 18

A. –17

B. –9

C. 9

D. 17

Find 4 – (–13).

Find –21 – (–8).

Subtract Negative Integers

–21 – (–8) = –21 + 8 To subtract –8, add 8.

= –13 Simplify.

Answer: –13

A. 9

B. 7

C. –7

D. –9

Find –8 – (–1).

Evaluate an Expression

ALGEBRA Evaluate g – h if g = –2 and h = –7.

g – h = –2 – (–7) Replace g with –2 and h with –7.

= –2 + (7) To subtract –7, add 7.

= 5 Simplify.

Answer: 5

A. 10

B. 8

C. –8

D. –10

ALGEBRA Evaluate f – x if f = –1 and x = –9.

GEOGRAPHY In Mongolia, the temperature can fall to –45°C in January. The temperature in July may reach 40°C. Find the difference between these two temperatures in Mongolia.

Subtract the lower temperature from the higher temperature.

40 – (–45) = 40 + 45 To subtract –45, add 45.

= 85 Simplify.

Answer: The difference between the temperatures is 85°C.

A. –101°C

B. –81°C

C. 81°C

D. 101°C

TEMPERATURE The temperature in Michigan fell to a low of –10°C in January, while in California the temperature reached a high of 91°C. Find the difference between the temperatures in these two states.