It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Make a sentence consisting of three words that have the whole alphabet.

How do you go from 98 to 720 using just one letter?

Can you place six X (crosses) in below board without making three in a row in any way ?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Give it food and it will live; give it water and it will die.

What makes this number unique: 8,549,176,320?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

Can you count the number of blocks in the picture below?