Adding and subtracting integers

Adding and Subtracting Integers

Vocab

1. Integer: A whole number that can be positive, negative, or zero

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum:

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference:

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference: The result of subtracting two or more numbers

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference: The result of subtracting two or more numbers

4. Positive:

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference: The result of subtracting two or more numbers

4. Positive: Greater than zero

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference: The result of subtracting two or more numbers

4. Positive: Greater than zero

5. Negative:

Vocab

1. Integer: A whole number that can be positive, negative, or zero

2. Sum: The result of adding two or more numbers

3. Difference: The result of subtracting two or more numbers

4. Positive: Greater than zero

5. Negative: Less than zero

Integers Reminder

Integers can be any WHOLE number that is positive or negative, including zero.

Adding Integers

When we add two positive numbers, it's just normal adding!
Examples: 8+5= 13
7+4=11

Multiple Choice

When adding two positive integers, you need to...

• add

• subtract

When both integers are negative...

When both integers are negative, you will add them and add a "negative" sign at the front.
Example: -7+(-4)= -11

Multiple Choice

When you add two negative numbers...

• The result is a positive number because you subtract them

• The result is a more negative number because you add them together

Multiple Choice

7+8=

• 15
• 14
• 16
• 12

Multiple Choice

9 + 3 =

• 10
• 15
• 9
• 12

Multiple Choice

-9 + (-4) =

• -10
• -12
• -13
• -5

Multiple Choice

-13 + (-7)=

• -6
• -10
• -15
• -20

When you add a negative and a positive....

You will subtract the number, and give the answer the bigger number's sign!

Example: 7 +(-4) = 3
-5+9=4

Multiple Choice

To combine a negative and positive...

• You add the values and give it the smaller number's sign

• You subtract the values and give it the bigger number's sign

Multiple Choice

7+ (-5)

• 12

• -12

• -2
• 2

Multiple Choice

9 + (-4)

• 5
• 13

• -13

• -5

Multiple Choice

-17+6

• -11
• 11

• -23

• 23

Easy Reminder...

Think of it as MONEY!
If you overdraw your account -$14, and put $7 in, how much will you have money wise now?

Subtracting Positive Integers

This is just NORMAL SUBTRACTION
Example: 7-4= 3
9-5= 4

Multiple Choice

7-4

• 3

• 1

• 11

• 6

Multiple Choice

20-5

• 10

• 15

• 20

• 25

Subtracting Negative Integers

Subtracting a negative integer is the same as adding a positive!
When you see "minus a negative" change it to "plus a positive," then solve it as addition.
Example 5-(-3) = 5+3 = 8

Subtracting Negative Integers

If the first number is also negative, that number stays the same, and you switch it to addition.

Example: -2-(-5) = -2 + 5 = 3

Multiple Choice

To subtract a negative integer....

• You change subtraction to addition and solve

• You subtract the absolute value of the negative integer.
• You multiply the negative integer by -1.
• You ignore the negative integer completely.

Multiple Choice

7 - (-5) =

• 12
• -12
• -2

• 2

Multiple Choice

14 - (-7) =

• 21
• -21
• 21 - 7
• 7

Multiple Choice

10 - (-3) =

• 7
• 10
• -13
• 13

Multiple Choice

True or False: If the first number has a negative sign, that negative sign has to change too.

• True
• False

Multiple Choice

-5 - (-5) =

• -10
• -5
• 5
• 0

Multiple Choice

-25 - (-4) =

• -21
• -29
• 29

• 21

Real World Application

The most common real world application for this skill is money. When you have a checking account, you want to keep it in the positives, but occasionally this doesn't happen. When the money amount is in the negatives, you have to add a certain amount in to get back to a positive balance. On the other hand, if your account is negative and you continue to spend money, you'll be subtracting from a negative balance, which will make it more negative.

Darla accidentally overdrew her account when she bought concert tickets. Her current balance is -$56. Her mother gives her $100 ​as a birthday gift. How much money will she have in her account if she deposits the whole $100?

Example 1:

Darla accidentally overdrew her account when she bought concert tickets. Her current balance is -$56. Her mother gives her $100 ​as a birthday gift. How much money will she have in her account if she deposits the whole $100?

Example 1:

​To set this problem up, we need to know some important details. First, we need to know what we're starting with. In this case, they tell us Darla's account balance is currently -$56

Darla accidentally overdrew her account when she bought concert tickets. Her current balance is -$56. Her mother gives her $100 ​as a birthday gift. How much money will she have in her account if she deposits the whole $100?

Example 1:

Next, we will need to figure out what operation we will need to do based on the situation. Darla's mom gives her the $100, and she DEPOSITS the money into the account, so we would be adding $100 to the account.

Multiple Choice

What would the equation be for this problem?

• -$56- ($-100)

• -$56 + $100

• -$100 + 56

• $56 + $100

Multiple Choice

-$56 + $100 =

• $46
• $54
• $44
• $40

Eddie has $25 in his checking account. He spends $8 on at the gas station on drinks and snacks. How much does he have left?

​

Example 2

Eddie has $25 in his checking account. He spends $8 on at the gas station on drinks and snacks. How much does he have left?

​

Example 2

​We see that Eddie is starting with a POSITIVE balance on his card, so we will write that as $25

Eddie has $25 in his checking account. He spends $8 on at the gas station on drinks and snacks. How much does he have left?

​

Example 2

​we see that he spends $8, meaning he withdraws $8, so we will subtract $8.

Math Response

What is the equation?

Type answer here

Correct Answer: 25-8

Deg^°

Rad

Multiple Choice

$25 - $8 =

• $17

• $15

• $20

• $10

We Do: Example 1

Marissa has $50 in her checking account. She pays $25 for gas. Does she have enough to buy a jacket for $30?

We Do: Example 1

Marissa has $50 in her checking account. She pays $25 for gas. Does she have enough to buy a jacket for $30?

Multiple Choice

How would you set this problem up?

• $50- $25

• $50 + $25

• -$50 + $25

• -$50 - $25

Multiple Choice

Does Marissa have enough money to buy the jacket for $30?

• Insufficient information to determine if Marissa has enough money.
• Yes

• No