1.9999... does not work in reality.
So now you restrict your challenge?
It is a result of fractional representation.
1.999... is no different to 2.
They are 1.999... ways to represent the same thing.
The fraction notation of 0.999... is 1, or 9/9
You are dismissing 1.999...99923 because it does not work in reality, when 1.999... the series you are claiming = 1.99...999 also does not exist in reality.
The only person claiming that is you. 1.999... IS NOT THE SAME AS 1.99...999
Notice how the final one terminates?
That means it doesn't go on forever.
That means it is not 1.999...
So, let us discuss the entirely similar situation: let us put two apples on a table - a sturdy table mind you that would not shake or move the apples or bring in other apples by accident and so on. Now we then put another two apples on the table, and count those now there - we will likely get the result 4. We can perform additional experiments like this, but we are fairly confident here that 'adding' works as we think it does. Yes, the results are consistent, and perhaps even corollary, but this is not the same thing as placing two numbers ones on a table and then two more number ones.
Numbers represent things. In this case we have 2 apples, which are represented by the number 2.
We then add more apples, again represented by the number 2.
This gives us 2+2=4.
However, if we did the same procedure with sticks, fingers, line and most things this would show us that sums are completely silly. Look at this figure to see 2+2 = 4, which is similar to your argument:
No, we don't get anything silly out of it.
If this is all we need, as you claim, to show that 2 + 2 = 4 and in your case 5 + 5 + 5 +5 = 20, then this is completely valid reasoning:
2 + 2 + 2 = 4.
Notice how you count two of them twice.
So no, that is nothing like what I am doing.
You have got 2+2, but then 2 extra.
This is not addition.
It is completely invalid reasoning.
Try again.
For similar reasons, your supplied example is not sufficient to show that 2 + 2 = 4 in reality, or that 5 * 4 = 20.
So for similar invalid reasons, i.e. no actual refutation at all.
I do have to ask, though this won't stop me from loving your movies Jack, if you feel that mathematics works in reality, then why are we continuing to work on advancing mathematics?
Just because the math we have works doesn't mean we know everything.
For example, think back to when we didn't have multiplication.
So we have 4 rows of 5.
How many do we have?
Well we have 5 plus 5 plus 5 plus 5.
That isn't all that nice to write out. 4 times 5 would be nicer.
So even though addition works, multiplication is nicer.