Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

What is wrong in the below Picture?

I’m tall when I’m young, and I’m short when I’m old. What am I?

Can you move 2 matchsticks to form four equal sized squares.

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

Can you find out which options fits best with the missing column?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?