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Ch 9: Add and Subtract Integers
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You Will Learn to add and subtract integers using
·Pictures (and Diagrams)
·Objects (Integer Chips)
·Numbers (Yes! Numbers!)
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9.1 - Explore Integer Addition
After this lesson, you will be able to...
·Add integers using integer chips
our chips
and
mean "positive."
and
mean "negative."
textbook chips
Key Terms:
opposite integers:
·two integers with the same "numeral",
zero pair:
·a pair of integer chips, with one but different signs. For example,
chip representing +1 and one
chip representing -1
·two integers represented by points that
are the same distance
in opposite
+2
directions from zero on a number line
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·the pair represents zero
because (+1) + (-1) = 0
use brackets!
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Example 1: Add Integers Using Integer Chips
Add using integer chips. Complete the addition statement in each
case. Cross out or circle zero pairs where applicable.
a) (+1) + (+2) = ___
c) (+5) + (-4) = ___
b) (-3) + (-2) = ___
d) (-6) + (+2) = ___
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Try "Show You Know" on p. 312
Example 2: Apply Integer Addition
Ray spent $5 on bus fares to visit his aunt. During the visit, she
gave Ray $12 for doing some yard work. How much money did
Ray gain from the visit?
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Key Terms:
opposite integers:
·two integers with the same "numeral",
zero pair:
·a pair of integer chips, with one but different signs. For example,
chip representing +1 and one
chip representing -1
·two integers represented by points that
are the same distance
in opposite
+2
directions from zero on a number line
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·the pair represents zero
because (+1) + (-1) = 0
use brackets!
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Assignment:
9.1 Explore Integer Addition
p. 313, #1–4 (as a class), 5, 7, 9, 11, 13
Still Good? # 12, 14-16
Pro Star? # 17-20
9.2 - Add Integers
After this lesson, you will be able to...
·add integers using a number line
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You can use an arrow on a horizontal or vertical number line to
represent an integer. The direction of the arrow shows the sign of the
integer. The length of the arrow shows the value of the numeral of the
integer.
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You can also use a horizontal or vertical
number line to represent integer addition.
Start at "0" and go from there...
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What is the addition statement represented by the number line?
Example 1: Add Integers Using a Number Line
a) (+4) + (+2) = ___
c) (+2) + (-4) = ___
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b) (-5) + (-3) = ___
d) (-6) + (+6) = ___
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Try "Show You Know" on p. 318
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The temperature in
Yellowknife, NWT, one
morning in October was
-4˚C. The temperature
increased by 9˚C to reach
the high temperature for
that day. What was the
high temperature?
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Example 2: Apply Integer Addition
Key Ideas
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You can use an arrow on a horizontal or vertical number line to
represent an integer. The direction of the arrow shows the sign of the
integer. The length of the arrow shows the value of the numeral of the
integer.
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Assignment:
9.2 Add Integers
p. 319, #1-4 (as a class), 5, 7, 9, 10, Math
Link
Still Good? #6, 8, 13–15, 17–19
Pro Star? #20–23
9.3 - Explore Integer Subtraction
After this lesson, you will be able to...
·Subtract integers using integer chips
our chips
and
mean "positive."
and
mean "negative."
textbook chips
Key Terms:
opposite integers:
·two integers with the same "numeral",
zero pair:
·a pair of integer chips, with one but different signs. For example,
chip representing +1 and one
chip representing -1
·two integers represented by points that
are the same distance
in opposite
+2
directions from zero on a number line
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·the pair represents zero
because (+1) + (-1) = 0
use brackets!
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Key Ideas
·You can use integer chips to represent integer subtraction.
·You can model subtraction by removing integer chips of the appropriate
colour.
·Add zero pairs if there are not enough chips of one colour to remove.
·There are two differences between two different integers. For example, the
differences between +1 and -2 are +3 and -3.
(+1) - (-2) = (+3)
(-2) - (+1) = (-3)
Example 1: Subtract Integers Using Integer Chips
Determine each difference using integer chips. Cross out or circle
zero pairs where applicable.
a) (-7) - (-3) = ___
c) (-6) - (+2) = ___
b) (+3) - (-4) = ___
d) (-2) - (-5) = ___
Try "Show You Know" on p. 325
Show You Know
a) (+8) - (+2) = ___
c) (+4) - (-5) = ___
b) (-1) - (+2) = ___
d) (+4) - (+6) = ___
Example 2: Apply Integer Subtraction
On a typical April day in Whitehorse, Yukon Territory, the
temperature is -5˚C in the morning and +6˚C in the afternoon.
Determine and explain the difference between these two
temperatures.
Method #1: Higher Minus Lower
Method #2: Lower Minus Higher
Assignment:
9.3 Explore Integer Subtraction
·p. 327, #1-4 (as a class), 5, 7, 9,
11, 13-15, 18
·Still Good? #16-17
·Pro Star? #19-21
9.4 - Subtract Integers
After this lesson, you will be able to...
·use addition to subtract integers (WHAT???)
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·You can subtract an integer by adding the opposite.
·You can represent integer subtraction by adding the opposite on a vertical
or horizontal number line.
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Explore the Math
Copy the table.
Use integer chips to help you complete each
subtraction statement.
(+4) - (+3) = ___
(+4) + (-3) = ___
(-5) - (-3) = ___
(-5) + (+3) = ___
(-3) - (+1) = ___
(-3) + (-1) = ___
0 - (+2) = ___
0 + (-2) = ___
(+2) - (-4) = ___
(+2) + (+4) = ___
(-4) - (-5) = ___
(-4) + (+5) = ___
What do you notice about the two columns?
Example 1: Use Addition to Subtract Integers
Subtract (-2) - (-5).
Think: To subtract -5, add the opposite, +5.
So, (-2) - (-5) = (-2) + (+5)
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Try "Show You Know" on p. 331
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Show You Know
(+3) - (+6) =
(-2) - (+3) =
(-4) - (-8) =
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The elevation of a lake is the height
of its surface from sea level. The
elevation of the Caspian Sea is 28
m below sea level. The elevation
of Lake Winnipeg is 217m above
sea level. Calculate and explain
the difference between these
elevations.
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Example 2: Calculate and Explain a Difference
Key Ideas
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·You can subtract an integer by adding the opposite.
·You can represent integer subtraction by adding the opposite on a vertical
or horizontal number line.
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Assignment:
9.4 Subtract Integers
·p. 333, #1-4 (as a class), 5, 7, 9,
11, 13, 15, Math Link
·Still Good? #16-22
·Pro Star? #23, 24
Attachments