Why is a river so rich ?

A number with an interesting property:

When I divide it by 2, the remainder is 1.
When I divide it by 3, the remainder is 2.
When I divide it by 4, the remainder is 3.
When I divide it by 5, the remainder is 4.
When I divide it by 6, the remainder is 5.
When I divide it by 7, the remainder is 6.
When I divide it by 8, the remainder is 7.
When I divide it by 9, the remainder is 8.
When I divide it by 10, the remainder is 9.

It's not a small number, but it's not really big, either.
When I looked for a smaller number with this property I couldn't find one.

Can you find it?

What always comes into a house through the keyhole?

What has many keys but can’t open a single lock?

Find out the missing number in the picture attached:

Replace the letters of words with a number so that the below equation holds true

BASE +
BALL
---------
GAMES
----------

Why is it against the law for a man living in Delhi to be buried in Mumbai?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Prove that the below maths equation is true.

8 + 8 = 91