is 9 plus ten 21 or 19?

19

its 19 ahh thats actually a vine that its 21 so thats why they are saying that

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9 + 10 = 10 + 9 = 19

lol. You are a funny (but not super bright) troll. PS IT IS contracts to it's [note apostrophe]

Search on youtube "9 plus 10 meme" and you will see where this comes from. A meme that went viral of a kid answering '21' the correct answer is indeed 19.

Maybe it does.

Take this proof in to your math teacher:

Given:

x = 0.999...

Therefore:

10x = 9.999...

Subtract the former from the latter:

10x - x = 9x

Using substitution:

9.999... - 0.999... = 9

Therefore:

9x = 9

Divide both sides of the equation by 9 to get the value of x:

x = 1

But wait. How can x = 1 if it's given that x = 0.999... at the top?

Here's proof that 2 = 1

a = b

a^2 = ab

a^2 - b^2 = ab - b^2

(a-b)(a+b) = b(a-b)

a+b = b

b+b = b

2b = b

2 = 1

Please continue your education because if you continue to post questions like this one then you won't stand a chance in this world.