Subtracting Integers Lesson

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In this section, we continue to learn about the topic of integers. Now, we turn to subtracting integers. How do we subtract integers? In order to be able to subtract
with integers, we must first have a firm understanding of how to add integers. When we are subtracting integers, we change our problem into addition of the opposite.

Subtracting Integers

1) Leave the first number (-2) unchanged: -2 - 3

2) Change the subtraction operation into addition: -2 + 3

3) Change the second number (3) into its opposite (-3): -2 + (-3)

4) Perform the addition: -2 + (-3) = -5

Example 2: Subtract 5 - (-7)

1) Leave the first number (5) unchanged: 5 - (-7)

2) Change the subtraction operation into addition: 5 + (-7)

3) Change the second number (-7) into its opposite (7): 5 + 7

4) Perform the addition: 5 + 7 = 12

This last example demonstrates a common source of confusion. We performed a subtraction, but we increased in value. When we subtract away a negative, the result is addition of a positive number.

Subtracting Integers

- Leave the first number unchanged (minuend or left number)
- Change the subtraction operation to addition
- Change the second number (subtrahend) into its opposite
- Perform the addition

1) Leave the first number (-2) unchanged: -2 - 3

2) Change the subtraction operation into addition: -2 + 3

3) Change the second number (3) into its opposite (-3): -2 + (-3)

4) Perform the addition: -2 + (-3) = -5

Example 2: Subtract 5 - (-7)

1) Leave the first number (5) unchanged: 5 - (-7)

2) Change the subtraction operation into addition: 5 + (-7)

3) Change the second number (-7) into its opposite (7): 5 + 7

4) Perform the addition: 5 + 7 = 12

This last example demonstrates a common source of confusion. We performed a subtraction, but we increased in value. When we subtract away a negative, the result is addition of a positive number.

Subtracting Integers Resources:

Videos:

Khan Academy - Video
Math Antics - Video
Virtual Nerd - Video
Text Lessons:

Khan Academy - Text Lesson
Algebra Class - Text Lesson
Math Goodies - Text Lesson
Worksheets:

K5 Learning - Worksheet
SuperTeacher Worksheets - Worksheet
Math Drills - Worksheet
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