Can you fill the blank with the correct number?

6 30 870 756030 _____

Andrew sees a very rare bird named "Ruppell's vulture". Soon Andrew was dead. Can you explain the mystery, Mr. Sherlock?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

Aaron, Brad, Christopher, Danny and Elvis decided to play a game of tiddlywinks. In this game they decided that one win will get 1 point for winning, 0 for losing and 1/2 in case of a tie.

They finished the game in alphabetical order and it was found that the scores were different for each person.

Based on the following two statements, can you find out the result of the individual games?
Brad: No one could finish like me, without a loss.
Elvis: No one played worse than me, I finished without a single win.

What is the word or phrase?