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

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

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

My location can be determined by the below rebus.
So where am i ?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

What has 88 keys?

Find the next number in the following series:
6, 14, 26, 98, __?

What does this say?

XLR8

You are given 2 eggs.
You have access to a 100-storey building.
Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100th floor, Both eggs are identical.
You need to figure out the highest floor of a 100-storey building an egg can be dropped without breaking.
Now the question is how many drops you need to make. You are allowed to break 2 eggs in the process

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?