This lesson contains 12 slides, with interactive quizzes and text slides.
Items in this lesson
Unit 2: Lesson 5-7
Adding and Subtracting Integers
Slide 1 - Slide
Scuba Diving
Imagine a scuba diver dives to a depth of 65 feet. Then she rises 15 feet back up toward the surface, where she stops to photograph some coral. What is the diver’s depth when she stops to take a photograph?
Why would the scuba diver need to know the depth?
Slide 2 - Slide
The Rule for Adding Integers with the Same Sign
To combine integers with the same sign, add their absolute values. Then give their sum the same sign as the addends.
8 + 15 = -8 +-15 =
23
7
-7
-23
Slide 3 - Drag question
The Rule for Adding Integers with the Opposite Sign
To combine integers with different signs, find their absolute values. Then subtract the lesser absolute value from the greater one. assign the sum the same sign as the number with the greater absolute value.
-8 + 15 = 8 +-15 =
23
7
-7
-23
Slide 4 - Drag question
Scuba Diving
Imagine a scuba diver dives to a depth of 65 feet. Then she rises 15 feet back up toward the surface, where she stops to photograph some coral. What is the diver’s depth when she stops to take a photograph?
Slide 5 - Slide
The coldest temperature
The average winter temperature in Antarctica is −30°F. The coldest temperature ever recorded was -129 degrees F. What is the difference between the 2 temperatures?
Why would we need to know the difference?
Slide 6 - Slide
How can we subtract 2 negative numbers?
Slide 7 - Mind map
Subtraction is the inverse of addition. What does that mean? How is it different from the opposite?
Slide 8 - Open question
The Rule for Subtracting Integers
When solving a subtraction problem with negative numbers, turn it into an addition problem by adding its opposite
Example 1: -1-(-6)
Slide 9 - Slide
Example 3: 6-(-1)
Slide 10 - Slide
Example 2: -2-5
Slide 11 - Slide
To Summarize
When adding negative numbers, add the absolute values of the numbers, then apply the sign in the problem
When adding a negative and a positive number, subtract the absolute values of the numbers and apply the sign of the number with greatest absolute value
When subtracting negative numbers turn the problem into an addition problem by adding the opposite of the negative number