If it took eight men ten hours to build a wall, how long would it take four men to build it?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

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

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

What do you see in the given picture?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

The Little ant seems to be always confused. Do you know why?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

Can you figure out the logic I used to decide the order of the following words:
gun, shoe, spree, door, hive, kicks, heaven, gate, line, den

A man died, leaving $10,000,000 for his widow, 5 sons and 4 daughters. Each daughter received an equal amount, each son received twice as much as a daughter, and the widow received three times as much as a son.

How much did the widow receive?