Adding and Subtracting Integers

Show your work for each problem.

1.
What is ?
1. a)
2. b)
3. c)
4. d)
Answer:
When adding two negative numbers, add the absolute values () and keep the negative sign: .
2.
What is ?
1. a)
2. b)
3. c)
4. d)
Answer:
Different signs: . Since and is positive, the answer is .
3.
Calculate:
Answer: -8
Same signs (both negative): Add , then apply the negative sign: .
4.
Calculate:
Answer: -3
Different signs: . Since and is negative, the answer is .
5.
Calculate using the rules for adding integers.
Answer: 5
1. Are the signs the same or different? different
2. What is ? 4
3. What is ? 9
4. Subtract: 5
5. Since and is positive, the final answer is? 5
6.
What is ?
1. a)
2. b)
3. c)
4. d)
Answer:
. Different signs: . Since and is negative, the answer is .
7.
What is ?
1. a)
2. b)
3. c)
4. d)
Answer:
. Different signs: . Since and is positive, the answer is .
8.
Calculate:
Answer: -11
. Same signs: , keep the negative sign: .
9.
Calculate:
Answer: 14
. The double negative becomes a positive!
10.
Calculate step by step.
Answer: 7
1. Rewrite as addition. What does it become? (-5) + 12
2. Are the signs the same or different? different
3. Subtract the absolute values: 7
4. Since and is positive, the final answer is? 7
11.
The temperature was in the morning. By afternoon it rose 15 degrees. What is the afternoon temperature?
Answer: 7
1. What expression represents this situation? -8 + 15
2. Are the signs the same or different? different
3. Subtract: 7
4. What is the afternoon temperature in °C? 7
12.
What is ?
1. a)
2. b)
3. c)
4. d)
Answer:
. Then .
13.
Calculate:
Answer: -10
. Then .
14.
Calculate:
Answer: -7
. Then .
15.
A submarine is at meters. It rises 30 meters, then dives 20 meters. What is its final depth?
Answer: -35
1. What expression represents this? (start + rise + dive) -45 + 30 + (-20)
2. Calculate -15
3. Now add to -35
4. What is the final depth in meters? -35
16.
Your bank account has 50 euros. You withdraw 75 euros, then deposit 30 euros. What is your balance?
Answer: 5
1. Write the expression (balance - withdrawal + deposit) 50 - 75 + 30
2. Rewrite as addition 50 + (-75)
3. Calculate -25
4. Now add to 5
5. What is your final balance in euros? 5