Math Magic
Pick a number
(1 – 10)
x
Multiply by 2
2x
Add 8
2x  8
Divide by 2
2x  8
2
Subtract the
original number
2x  8
x
2
Find your answer on the charts
Pick a country which starts with the corresponding letter
Pick an animal which starts with the next letter
Skip a letter and pick a color that start with the next letter
1
A
6
F
2
B
7
G
3
C
8
H
4
D
9
I
5
E
10
J
Who has
“Grey Elephants
in Denmark”?
Function Machine
Input
x
Result
2x  8
f ( x) 
x
2
?
Input
x
1
2
3
4
x
Function
2( x )  8
 ( x)
2
4
2(1)  8
 (1)
2
2( 2 )  8
 ( 2)
2
2( 3)  8
 ( 3)
2
2( 4 )  8
 ( 4)
2
2( x )  8
 ( x)
2
Result
y
4
4
4
4
4
2( x )  8
 ( x)  4
2
2x  8
x4
2
Questions ?
1. Why does this work?
2. Is the domain really limited to 1 - 10?
3. Find another equation which has infinite
solutions?