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

What number comes next in this sequence:
7 8 5 5 3 4 4 _

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

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

Solve the puzzle by telling what does below picture means.

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

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?