Functions Machines
Making sausages
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If you think of a sausage machine: something goes in, the machine works its magic, and sausages come out the other end! A function machine is a little like that, just with no sausages. We have 3 important things that happen though, just like a sausage machine.
Function machines
With a function machine, we have:
- something going in (input)
- something happening in the machine (operation)
- something coming out (output)
Is that all?
Yes! It looks just like this.
Let's watch a video to see how it works and how it can go in reverse as well.
A function machine uses three special terms:
- input
- operation
- output (We don't call this the answer)
Worked Examples
Question 1
Look at this function machine.
| $2$2 |  |
$+$+$1$1 |
|
? |
In the case above, what is the output of the function machine?
If the input was changed to $7$7, what would the new output of the function machine be?
Question 2
Look at this function machine.
| $5$5 | |
? |
|
$7$7 |
What is the operation of this function machine?
$2$2
A$7$7
B$+$+$5$5
C$+$+$2$2
D$-$−$2$2
E$\times$×$2$2
FWe can reverse the direction of a function machine.
$5$5 
?
$7$7 Now $7$7 is the input and $5$5 is the output.
What is the operation of this function machine now?
$\times$×$2$2
A$-$−$2$2
B$5$5
C$2$2
D$+$+$2$2
E$-$−$7$7
F
Question 3
Look at this function machine.
| ? | |
$+$+$5$5 |
|
$12$12 |
In the case above, what is the input of the function machine?
If the output was changed to $11$11, what would the new input of this function machine be?