Math MagicMath Magic

Pick a number(1 – 10)

x

Multiply by 2

2x

Add 8

2 8x

Divide by 2

2 8

2

x

Subtract the original number

2 8

2

xx

Find your answer on the charts

Pick a country which starts with the corresponding letter

11 AA

22 BB

33 CC

44 DD

55 EE

Pick an animal which starts with the next letter

Skip a letter and pick a color that start with the next letter

66 FF

77 GG

88 HH

99 II

1010 JJ

Who has

“Grey Elephants

in Denmark”?

Function MachineFunction Machine

2 8

2( )

xf x x

Input

x

Result

?

InputInput FunctionFunction ResultResult

xx yy

11

22

33

44

xx

2 8

2

22

( )( )

2 8

2

11

( )( )

2 8

2

33

( )( )

2 8

2

44

( )( )

2 8

2

( )( )

xx

2 8

2

( )( )

xx

2 84

2

( )( )

xx

44

4

4

4

4

4

Questions ?1. Why does this work?

2. Is the domain really limited to 1 - 10?

3. Find another equation which has infinite solutions?

2 84

2

xx