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Integers
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Level 3
Add/Sub and Double Negatives
Multiply +ve / -ve Integers
Divide by +ve or -ve Integers
12-May-17
Created by Mr. Lafferty Maths Dept.
Starter Questions
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Level 3
1. Calculate 30% of 80
2.
15% of 700p
3.
Find the value of x
4x +2 = 122
12-May-17
Created by Mr. Lafferty Maths Dept.
Integers
Addition & Subtraction
www.mathsrevision.com
Level 3
Learning Intention
1.
To explain the ‘double
negative’ for integers.
Success Criteria
1. To understand the ‘double
negative’ for integers.
2. To simplify and solve
problems using the
‘double negative’ property.
12-May-17
Created by Mr. Lafferty Maths Dept.
Integers
Revision
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Level 3
(a)
12 + 4 = 16
Go up
4
Start
at 12
(b)
10 +(-8) = 2
Start
at 10
(c)
Go down
8
7 - 10 = -3
Start
12-May-17
at 7
24
20
16
12
8
4
0
-4
-8
-12
-16
-20
-24
Go down
10 Created by Mr. Lafferty Maths Dept
22
18
14
10
6
2
UP +
-2
-6
-10
-14
-18
-22
Down -
Integers
Level 3
www.mathsrevision.com
Examples
(1)
3-7
= -4
Remember
(2)
4 + (-9)
= -5
(3)
-7 - 8
= -15
“+ -” = -
(4)
-2 + (-12)
= -14
(5)
-5 - 25
= -30
(6)
8 + (-9)
12-May-17
= -1
Created by Mr. Lafferty Maths Dept
With your partner
you have 30 second
to the rule
Addition & Subtraction
Integers
www.mathsrevision.com
Level 3
Double Negative
Rule
1 - (- 2) =
1+2=3
- 4 – (- 5) = - 4 + 5 = 1
“- -” = +
-3 - (- 5) = - 3 + 5 = 2
-1 - (- 10) = -1 + 10 = 9
12-May-17
Created by Mr. Lafferty Maths Dept.
Practice
Integers
Addition & Subtraction
www.mathsrevision.com
Level 3
Now try Ex 3/4
First Column Only
Ch2 (page 14)
12-May-17
Created by Mr. Lafferty Maths Dept.
Starter Questions
Level 3
www.mathsrevision.com
1. 2.5% of 100p
2. Round to 2 decimal place
(a) 18.6745
(b) 36.994
3. Find the value of x
3x + 9  27
12-May-17
Created by Mr. Lafferty Maths Dept.
Integers
www.mathsrevision.com
Multiplication & Division
Learning Intention
1. Explain how to multiply
positive and negative
integers.
12-May-17
Success Criteria
1. Understand how to
multiply positive and
negative integers.
Created by Mr. Lafferty Maths Dept.
With your partner
can try and come up
(+ve) x (+ve) = (+ve)
with the rules for
(-ve) x (–ve) = (+ve)
Multiplication & Division
multiplying integers
(-ve) x (+ve) = (-ve)
Multiplying Integers
(+ve) x (–ve) = (-ve)
www.mathsrevision.com
Integers
1 x (-2) = -2
(-2) x (-1) = 2
(-4) x 5 = -20 (- 2) x (-5) = 10
(-3) x 3 = -9
(-5) x (-5) = 25
Same signs
positive answer
5 x (-8) = -40 (-4) x (-8) = =32
12-May-17
Different signs
= negative answer
Created by Mr. Lafferty Maths Dept.
Remember
BODMAS
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S33
Same signs
= positive answer
Integers
MultiplicationDifferent signs
= negative answer
Multiplying Integers
1 + (-2) x (-10) = 21
3 + (-5)2 = 28
8 – (-3)2 = -1
5 x (-2)2 + 5 – 19 = 6
12-May-17
Created by Mr. Lafferty Maths Dept.
Integers
Addition & Subtraction
www.mathsrevision.com
Level 3
Now try Exercise 5
Ch2 (page 17)
Q1 – Q6
12-May-17
Created by Mr. Lafferty Maths Dept.
Starter Questions
Level 3
www.mathsrevision.com
1.
Simplfy the ratio
2. Calculate
13 : 52
2.5% of 400
3.
I got $650 for £100. How much would I
get for £2.
4.
Put in order, smallest first.
0.25, 0.19, 0.01, 0.026
5.
12-May-17
Find the value of x
7x +2.5 = 20
Created by Mr. Lafferty Maths Dept.
Integers
Multiplication & Division
www.mathsrevision.com
Level 3
Learning Intention
1. To explain the double
negative for multiplying
and division.
Success Criteria
1. Understand the ‘double
negative’ for multiplying
and dividing negative
numbers.
2. Use double negative to
solve problems.
12-May-17
Created by Mr. Lafferty Maths Dept.
With your partner
can try and come up
with the rules for
Multiplication
multiplying integers
(+ve) ÷ (+ve) = (+ve)
(-ve) ÷ (–ve) = (+ve)
& Division
(-ve) ÷ (+ve) = (-ve)
(+ve) ÷ (–ve) = (-ve)
Integers
www.mathsrevision.com
Level 3
(-2) ÷ 1 = -2
20 ÷ (-5) =-4
(-9) ÷ 3 = -3
(-25) ÷ 5 = -5
12-May-17
(-2) ÷ (-1) = 2
(- 20) ÷ (-5) = 4
(-9) ÷ (-3) = 3Same signs
= positive answer
(-40) ÷ (-8) = 5
Different signs
= negative answer
Created by Mr. Lafferty Maths Dept.
Remember
BODMAS
www.mathsrevision.com
Level 3
IntegersSame signs
Division = positive answer
Division Integers
Different signs
= negative answer
1 + (-20) ÷ (-10) = 3
100 ÷ (-5)2 = 4
100 - 36 ÷ (-3)2 = 96
-48 ÷ (6 - 2)2 + 5 = 2
12-May-17
Created by Mr. Lafferty Maths Dept.
Integers
Multiplication & Division
www.mathsrevision.com
Level 3
Now try Exercise 5
Ch2 (page 18)
Q7 – Q10
12-May-17
Created by Mr. Lafferty Maths Dept.