Number Formation: Creating the Six-Digit Number 900,999

To solve this problem, let's consider the number $900,999$. This number can be broken down as follows:

• The '900,000' component can be written as $9 \times 100,000$, as 900,000 is nine hundred thousands.
• The '999' component can be broken into $9 \times 100 + 9 \times 10 + 9 \times 1$, representing nine hundreds, nine tens, and nine units.

Now, combining these parts together, the exercise becomes:

$9 \times 100,000 + 9 \times 100 + 9 \times 10 + 9 \times 1 = 900,999$.

This is the decomposition that accurately reflects the number $900,999$.

Thus the correct choice among the options provided is: $9 \times 100,000 + 9 \times 100 + 9 \times 10 + 9 \times 1 = 900,999$.