Saya baru nemu hal ini di Wikipedia. 0.999... = 1, tapi bukan dibulatkan menjadi 1.



dan



Bagaimana menurut Anda?

nunggu yang lain deh,
saya agak bingung juga nih..
tapi kalau dikalkulator 1\9 itu kalau dkali 9 lagi= 1..
nah tapi yang ini bener juga gitu...

KutipStudents of mathematics often reject the equality of 0.999... and 1, for reasons ranging from their disparate appearance to deep misgivings over the limit concept and disagreements over the nature of infinitesimals. There are many common contributing factors to the confusion:

    Students are often "mentally committed to the notion that a number can be represented in one and only one way by a decimal." Seeing two manifestly different decimals representing the same number appears to be a paradox, which is amplified by the appearance of the seemingly well-understood number 1.[36]
    Some students interpret "0.999..." (or similar notation) as a large but finite string of 9s, possibly with a variable, unspecified length. If they accept an infinite string of nines, they may still expect a last 9 "at infinity".[37]
    Intuition and ambiguous teaching lead students to think of the limit of a sequence as a kind of infinite process rather than a fixed value, since a sequence need not reach its limit. Where students accept the difference between a sequence of numbers and its limit, they might read "0.999..." as meaning the sequence rather than its limit.

[pranala luar disembunyikan, sila masuk atau daftar.]
sumber masalahnya juga sudah dijelaskan di wiki tuh.