The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Two men are in a desert. They both have packs on. One of the guys is dead. The guy alive has his pack open, and the guy who is dead has his pack closed. What is in the pack?

How can you tell a raw egg from a hard-boiled egg?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

John is pretty weird. He likes toffees but hates chocolates. He loves books but never reads. He likes to build his troops in an online game but does not proceed with the war. He likes to go swimming but is afraid of water.

Seeking this behaviour, can you tell whether he likes balloons and parties?

What is more useful when it is broken?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?