1. Module D Chapter 5 Function Frenzy
Year 8
Module D Chapter 5
Function Frenzy
30 June 2019

2. Put todays date next to these learning objective
2. Mappings June 2019
Put todays date next to these learning objective
use function machines to describe the rule that maps one set of numbers to another 5b
use algebra to describe mappings using positive and negative numbers 5a
use algebra to describe mappings using fractions 6c
draw mapping diagrams for simple functions using positive numbers 6b
draw mapping diagrams for simple functions using negative numbers 6a
express functions in more than one way and factorise them
find the inverse of a linear function

3. draw mapping diagrams for simple functions using positive numbers 6b
To draw a mapping diagram:
1. Draw 2 identical number lines
Now use the mapping to link each input with it’s output
this mapping is x ⟶ x (take each number on the input line and add 2 )

4. This is the mapping diagram for x ⟶ 2x
(take each number on the input line and double it)
This is the mapping diagram for x ⟶ 2x + 3
(take each number on the input line, double it and add 3)
30 June 2019
Question6 page 73

5. 10 Ticks Level 6 pack 8 pages 5 and 6
Your Turn
10 Ticks Level 6 pack 8 pages 5 and 6
Level Up exercise 5.1 page 73 question 6
To get a 6a you must complete question 2 on the 10 Ticks sheet
30 June 2019

6. Put the data in order in a table
Use function machines to describe the rule that maps one set of numbers to another 5b
We can work out what this function machine does from it’s inputs and outputs
To find out:
Put the data in order in a table
Look at the difference between two x terms and their y terms
Function machine is x ⟶ ⟶ ⟶ y x 2 4 6 9 y 8 14 20 29 x 2 4 y 8 14
X terms: The difference between 2 and 4 is +2
Y terms: The difference between 8 and 14 is + 6
to get from +2 to +6 we multiply by 3
This means the function machine has x3 in it x3 +2
30 June 2019

7. Function machine is x ⟶ ⟶ ⟶ y
Omar will now ask how did I get the “How did you get the +2 Miss Pam?”
Look at the function machine:
9 x 3 = 27 but our output is 29 so we need to add 2
2 x 3 = 6 but our output is 8 so we need to add 2
4 x 2 = Are you getting it yet? x3 +2
30 June 2019

8. Put the input and output in a table in order Look at the differencesx 2 3 5 y 7 11
Put the input and output in a table in order
Look at the differences
This means the function machine has a x2 in it
The function machine is x ⟶ ⟶ ⟶ y
The rule is y = 2x + 1
Omar asks “how did you get the +1 Miss Pam?”
x terms: The difference between 2 and 3 is +1
y terms: The difference between 5 and 7 is + 2
to get from +1 to +2 we multiply by 2 x2 +1
2 x 2 = the output is 5 so +1
3 x 2 = the output is 7 so +1
5 x 2 = the output is 11 so +1
30 June 2019

9. Put the input and output in a table in order Look at the differencesx 2 4 5 y 11 14
Put the input and output in a table in order
Look at the differences
This means the function machine has a x3 in it
The function machine is x ⟶ ⟶ ⟶ y
The rule is y = 3x - 1
Omar asks “how did you get the -1 Miss Pam?”
x terms: The difference between 2 and 4 is +2
y terms: The difference between 5 and 11 is + 6
to get from +2 to +6 we multiply by 3 x3 -1
2 x 3 = the output is 5 so -1
4 x 3 = the output is 11 so -1
5 x 3 = the output is 14 so -1
30 June 2019

10. Put the input and output in a table in order Look at the differencesx 6 10 14 y 4 8
Put the input and output in a table in order
Look at the differences
This means the function machine has a ÷2 in it
The function machine is x ⟶ ⟶ ⟶ y
The rule is y = 𝑥
Omar asks “how did you get the +1 Miss Pam?”
x terms: The difference between 6 and 10 is +4
y terms: The difference between 4 and 6 is + 2
to get from +4 to +2 we divide by 2 ÷2 +1
Miss Pam looks at him until he figures it out!
30 June 2019

11. Level Up section 5.2 question 1 and 2
Your Turn
Level Up section 5.2 question 1 and 2
10 Ticks Level 5 pack 5 pages 25-26
30 June 2019