What does this rebus means ?

PROG WORKRESS

There are forty elephants and they have forty-fore heads. How can this be possible?

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

You’ll find me on Mercury, Earth, Mars, Jupiter, Saturn, and Uranus. But never Neptune, or Venus. What am I?

Vin Diesel is pulling a theft and has planned to run away with all the cash kept in the safe. But the only way to open the safe is the 13 character password. He has a set of five clues given to him by a trustworthy source.

Exactly two of the below statements are false.
The password is contained within this sentence.
The password is not in this hint.
The password is within only one of these statements.
At least one of the above statements is a lie.

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?