Negative Numbers

1
Negative Numbers
Integers Positive and Negative
Add /Sub using Thermometer
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Add / Sub Mathematically
Negative Coordinate Grid
2
Starter Questions
Q1. Calculate
Q2. How many euros do I get for 20 if exchange
rate is 1 ? 1.5
Q3. What is the time difference 0928 and 1050
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Q4. The answer to the question is 90. What is
the question.
3
Negative Numbers
Addition Subtraction
Learning Intention
Success Criteria

1. Understand how to add and subtract both positive
   and negative integers using a thermometer.

1 We are learning how to add positive and
negative numbers.
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4
Integers
Definition An INTEGER is a negative or
positive whole number, including 0.
e.g. -2, -1, 0, 5, 100
Note -2.5, -1.2, 23.5
Are NOT INTEGERS
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Write down 3 places where negative numbers are
used
Interpreting negative numbers
Ex1 Page 59 Round Class
5
Negative Numbers
(a) 4oC up from 12 o C
8
6
12 4 16
4
(b) 8oC down from 10 o C
2
10 - 8 2
0
-2
(c) 3oC up from -2 o C
-4
-6
-2 3 1
-8
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(d) 6oC down from 2 o C
2 - 6 -4
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Negative Numbers
Your turn ! Page 61 Exercise 2
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Starter Questions
Q1. Calculate
Q2. How many euros do I get for 10 if exchange
rate is 1 ? 1.4
Q3. What is the time difference 0945 and 2030
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Q4. The answer to the question is 30. What is
the question.
8
Negative Numbers
Addition Subtraction
Learning Intention
Success Criteria

1. To be able to write down mathematically the
   addition and subtraction of both positive and
   negative integers.

1 We are learning how to write down
mathematically addition and subtraction of
negative integers.
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9
Negative Numbers
(a) 12 4
16
8
6
4
Go up 4
Start at 12
2
0
-2
(b) 10 (-8)
2
-4
-6
-8
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Start at 10
Go down 8
(c) 7 - 10
-3
Start at 7
Go down 10
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Negative Numbers
Examples
Remember - - - -
-4
(1) 3 - 7
(2) 4 (-9)
-5
(3) -7 - 8
-15
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(4) -2 (-12)
-14
(5) -5 - 25
-30
(6) 8 (-9)
-1
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Negative Numbers
Your turn ! Page 61 Exercise 2 Q1 and Q2
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Starter Questions
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Coordinates
Extending the Grid Negative Numbers
Learning Intention
Success Criteria

1. Remember the main parts of a coordinate grid.

1. We are learning how we can extend the
coordinate grid to include negative numbers.
2. Understand the negative grid both in y-axis
direction and x-axis direction.
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14
Coordinates
Extending the Grid Negative Numbers
We can further extend the negative grid
y - axis
Plot the point
(-2,2)
3
x-coordinate is -2
2
1
y-coordinate is 2
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0
-2
-3
2
4
-1
1
3
-4
x - axis
-1
(-4,-2)
-2
-3
x-coordinate is -4
y-coordinate is -2
Write down coordinates of the other points
15
Coordinates
Extending the Grid
Now try Exercise 4 Ch5 (page 64)
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