Basic JavaScript: Understanding Uninitialized Variables. Why not automatic reflection of the results?

In line 1 where initialize these 3 variables is written, just below this line only variables were there or created but they were not defined. Now, I have defined assigning values in these lines only. And, in the lines 8, 9 and 10 (below mentioned thing is given
a = a + 1;
b = b + 5;
c = c + " String!";
Now my question is why are we manually writing in the lines 11, 12 and 13 that
a = 6
b = 15
c = “I am a String!”
and then submitting the result and it is showing okay .
If we have already assigned values then we should be doing it clicking on any button or giving a command and then values (final) will automatically get reflected beside those variables.

these are the final values that the variables need to have at the end of the code

THis is the existing code

You need to add something to var a;, give it an initial value, so that the final value (after the variable is subjected to operation a = a + 1) is the desired one

This is to learn how to manipulate variables.

This seems the wrong way to pass the tests, but if you have done the correct thing above it is unneccessary code. You shouldn’t manually writing this. Also because lines 11,12,13 are below the line “// Do not change code below this line”