Math Olympiad for 3rd Grade – 3

Black stones and white stones are arranged on the table in the following pattern:
```
⚫◯◯⚫⚫⚫◯⚫⚫◯◯◯⚫◯◯⚫⚫⚫◯⚫⚫◯◯◯⚫◯◯⚫⚫⚫ ...... 
```
The color of the 999th stone is __________ and there are ____________ white stones among the 999 stones.
For the following sequence of numbers: $$1, 4, 7, 10, 13, 16, 19, 22, 25, …….$$ The $2020^{th}$ number in the above sequence is ________.
For the following sequence of numbers: $$1, 2, 4, 7, 11, 16, 22, 29, ……$$ where the first number is $1$, the second number is one more than the first, the third number is one more than the second, and so on. The remainder of the $2020^{th}$ number divided by 5 is __________.
Chaining the following sequence numbers together $$1, 2, 3, 4, …… 97, 98, 99, 100, 101$$ to form a very big number $$123456……979899100101$$ There are __________ digits in the above big number.
The product of $10000$ natural numbers is $10000$. The maximum sum of those $10000$ numbers is __________.