Upload
joel-dawson
View
29
Download
0
Embed Size (px)
DESCRIPTION
Subtracting Positive and Negative Integers. WARM-UP:. 1.)(-5) + (-26) = 2.)(-18) + 7 = 3.)Write a variable expression for: r less than 12 4.) -40 + 9 = 5.)4 + (-36) =. Let's review what we learned in the last lesson. - PowerPoint PPT Presentation
Citation preview
Confidential 1
Subtracting Positive and Negative Integers
Confidential 2
WARM-UP:
1.) (-5) + (-26) =
2.) (-18) + 7 =
3.) Write a variable expression for: r less than 12
4.) -40 + 9 =
5.) 4 + (-36) =
Confidential 3
Let's review what we learned in the last lesson.
Confidential 4
Confidential 5
Confidential 6
Confidential 7
TODAY we will be studying 2 methods to learn how to subtract integers.
METHOD 1 - Zero Pairs
Remember that the red chips are NEGATIVE.
The grey chips are POSITIVE.
+
+
+-
--
--
Confidential 8
Let's subtract 6 - 2 =
We begin with 6 POSITIVE (grey) chips.
+
+
++
+ +
next page
Confidential 9
Let's subtract 6 - 2 =
+
+
++
+ +
Then we take away (or Subtract) 2 POSITIVE chips.
next page
Confidential 10
++
+ +
We are left with 4 POSITIVE (Grey) chips.
So..... 6 - 2 = 4
Let's subtract 6 - 2 =
Confidential 11
Now, let's subtract (-5) - (-4) =
We begin with 5 NEGATIVE (or red) chips.
- -
- -
-
next page
Confidential 12
Now, let's subtract (-5) - (-4) =
- -
-
--
Then, we take away (or Subtract) 4 NEGATIVE chips.
next page
Confidential 13
Now, let's subtract (-5) - (-4) =
-
And we are left with 1 NEGATIVE (red) chip.
Therefore, (-5) - (-4) = -1
Do you have any questions so far?
Confidential 14
SOMETIMES we need to add Zero Pairs in order to subtract or take away chips.
For example, let's subtract 5 - (-3) =
We begin with 5 POSITIVE (grey) chips.
+ + + + +
next page
Confidential 15
5 - (-3) =
We begin with 5 POSITIVE (grey) chips.++
+ +
Now, we need to take away (or Subtract) 3 NEGATIVE (red) chips but we don't have any!!
So we must ADD 3 Zero Pairs...............
- - -
+++
next page
+
+
Confidential 16
++++ +
- - -
+++Now, we can take away (or Subtract) the 3 NEGATIVE (red) chips.
And we are left with 8 POSITIVE (grey) chips.
Therefore, 5 - (-3) = 8
5 - (-3) =
Confidential 17
You try this one…
(-4) - 1 =
Use your pen to draw the red and grey circles.
Confidential 18
Try 4 - (-2) =
Use your pen to draw the red and grey circles.
Confidential 19
METHOD 2 - Rule for Subtracting Integers
When we subtract an integer, we add its opposite.
For example, (-10) - 7 =
(-10) + (-7) = (-17)
we add its opposite
Confidential 20
Of course, if we are going to ADD its opposite, we must remember the rules for ADDING INTEGERS.
Adding Different Signs -
1. Find the absolute value of the 2 numbers.2. Subtract the smaller number from the larger number.3. Take the sign of the larger number for your answer.
Adding the Same Sign -
The sum of 2 positive numbers is POSITIVE.The sum of 2 negative numbers is NEGATIVE.
LET'S REVIEW
Confidential 21
Let's try a few more subtraction problems. Remember the RULE -
When we subtract an integer, we add its opposite.
9 - (-6) =
9 + 6 = 15
we add its opposite
Confidential 22
You try a few.
(-4) - (-4) = (-2) - 8 = 12 - (-3) =
Confidential 23
1.) Can you find the missing numbers?
-32 + = 65
47 - = 80
Confidential 24
2.)Anne is 8 years older than Jane and 3 yearsolder than Mary. The sum of their ages is 67.How old is each person?
Confidential 25
3.) Use these digits (4, 7, 9) to make as many 3 digit numbers as possible. You may only use each digit only one time in each number.
Confidential 26
Let's see how well you understood the lesson today.
Find each difference.
1.) -13 - 13 =
2.) 9 - (-8) =
3.) 28 - 16 =
Confidential 27
4.) 12 - 15 =
5.) 0 - (-47) =
6.) -190 - 82 =
Confidential 28
7.) (-12) - (-26) =
8.) 4 - (-60) =
9.) 22 - 38 =
10.) (-109) - 10 =
Confidential 29
Let's review what we learned today.
We looked at 2 different methods for SUBTRACTING integers.
METHOD 1 - Using Zero Pairs
+
-
Confidential 30
SOMETIMES we need to add Zero Pairs in order to subtract or take away chips.
3 - (-1) =
Begin with 3 POSITIVE chips
Add 1 ZERO PAIR
Now we can take away 1 NEGATIVE chip
And you're left with 4 POSITIVE chips
3 - (-1) = 4
+
+
++
-
Confidential 31
Confidential 32
Great job today!
Remember to practice what you learned!