Lesson 1.3: Adding Integers

Lesson 1.3:
Adding Integers

​Definition:

​Commutative Property: When adding or multiplying two numbers together we can change to order of the numbers.
Ex: 3 + 5 = 5 + 3
or: a + b = b + a
Ex: 2 X 4 = 4 X 2
or: a * b = b * a

​Goal Today:

​Today we are going to work with adding integers. We will be working with different signs and figuring what happens when adding together a positive and positive, a positive and negative and a negative and negative.

​How to add integers:

​Adding Integers:
Same sign ==> add the numbers and keep the sign.

Different sign ==> subtract the numbers and keep the sign of the larger number.

​Ex: Perform the operation
-5 + 3 and -8 + -2

​Number Line:
.
.
.
.
Counters:
.
.
.
.
.Basic Skills:

Multiple Choice

Perform the operation:

9 + -4

• -5

• 5

• 13

• -13

Multiple Choice

Perform the operation:

-12 + -7

• -5

• 5

• -19

• 19

​Ex: Kiara was playing golf. She scored +4 on the first hole and -3 on the second whole. What was her score after the two holes?

Multiple Choice

Henry has $50 in his pocket and he owes his friend $20. After settling his debt, how much money does he have or does he owe money still? If so, how much does he owe?

• $70

• Owes $70

• $30

• Owes $30

Multiple Choice

A deep sea diver dives 81 feet below the surface. He then dives 14 feet deeper. What is the divers final destination?

• 67 feet below sea level

  (-67 feet)

• 67 feet above sea level

  (67 feet)

• 95 feet below sea level

  (-95 feet)

• 95 feet above sea level

  (95 feet)

​Conclusion: Write two complete sentences about what you learned.

​I learned that when adding integers, I need to notice if the integers have the same or different _____.

When the signs are the same I ____ the integers and keep the ____ stays the same.

When the signs are different, I ____ the integers and keep the ____ of the ____ integer.