Interesting question. Does 1.99999999999... = 2

[Jinc]

1.99 recurring and 2 are two completely different numbers. That does not mean that they are not equal to each other. Here is the way that I always prove this sort of thing to people.

1.99 recuring is 1.999999............. forever yes?

Call this 1.99 recurring x.

Multiply 1.99 recurring by 10, thus giving you 10x.

x = 1.99999999999999.........
10x = 19.9999999999999........

Now minus x away from 10x leaving behind 9x.

10x = 19.9999999999999........
- x = 1.99999999999999.......

= 9x = 18

If 9x = 18 then x = 2.

But x also = 1.99 recurring .



It's the same concept that that there is only 179.99 recurring degrees in a triangle, making it possible for you to have a two sided triangle .

GCSE Maths ahoy!

Yes, it can be said that in this circumstance 1.999etc is equal to 2, but not the same number quite obviously.

If you were using the 1.999 in certain theorems, then it wouldn't be plausible to state that it is equal to 2.. but for most cases involving such numbers, the method shown by N!ck can be used.

[Colin-Roberts]

technically it doesn't equal exactly 2 but in certain equations it would be ok to use it as 2.

[Virgin Mary]

Just seems like another case of changing the facts to fit the logic.

[RedStratocas]

Is this because 1/3= 0.333 2/3= 0.666 3/3= 0.999 but 3/3= 1

no it doesnt :/ anything divided by itself equals 1

and this question doesnt make any sense. because if it keeps going, how do you know what to compare it to? you can keep adding 9's to the end of 1.99 and it'll never turn into a 2.

[BL!NKEY]

no it doesnt :/ anything divided by itself equals 1

and this question doesnt make any sense. because if it keeps going, how do you know what to compare it to? you can keep adding 9's to the end of 1.99 and it'll never turn into a 2.

ok but 2/3+1/3=3

we can agree on that

2/3=.666...
1/3=.333...
so 3/3=.999... or 1 which is the same thing.

also 1/9=.111...
2/9=.222...
8/9=.888...
9/9=.999...
and 9/9=1

along with the other reasons.

You do not keep adding nines. There is not a last nine. It is an infinite amount of nines.