Multiple Decimal Expansions: Explained

[Swetasuria]

I read here in Physics Forums that a number can have more than one decimal expansion.

Really? Can someone explain how?

Is it that any number can have more than one decimal expansion or only some numbers?

 

[pwsnafu]

See the 0.9... article on Wikipedia or the https://www.physicsforums.com/showpost.php?p=3357236&postcount=1 on this forum.

 

[uart]

I read here in Physics Forums that a number can have more than one decimal expansion.

Really? Can someone explain how?

Is it that any number can have more than one decimal expansion or only some numbers?

Hi Swetasuria. You can take the "usual" decimal expansion of any terminating decimal and replace the last digit with one smaller, then add repeating 9's after that, and yes it's the same number.