Can you fill the blank with the correct number?

6 30 870 756030 _____

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

I am an odd number. Take away a letter and I become even. What number am I?

Spot what is wrong here in below Picture?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

It has horns but can’t beep. It is like to bleat but It is not a sheep. What is it?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?