What is the longest word in the dictionary?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

What's a single-digit number with no value?

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
=====
* * *

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

A bus driver was heading down a street in Mexico. He went right past a stop sign without stopping, he turned left where there was a "no left turn" sign, and he went the wrong way on a one-way street. Then he went on the left side of the road past a cop car. Still - he didn't break any traffic laws. Why not?

Replace the question mark with the number below given a simple math problem.