It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But do you know how many of these numbers are prime?

Find the missing value of "?" in the letter sequence below.

CAD
EBG
KBM
OCR
DDH
NL?

What has to be broken before you can use it?

What is harder to catch the faster you run?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

Two brothers were watching a horror film on video late one night. One brother dozed off and dreamed that he was being chased by the crazy man from the movie, who was trying to kill him. In the dream, he hid in a cupboard. There was no sound except his heart pounding, and he had no idea where his crazed captor was. He was terrified! At that moment, the video finished, and his brother put his hand on the shoulder of his sleeping sibling to wake him. The shock at that tense moment was enough that the sleeping brother suffered a massive heart attack and died instantly. True or false?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

I know a nine-letter word having only one vowel.
Do you ?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?