How can a man go eight days without sleep?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

In the addition below, all digits have been replaced by letters.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?

If,
9 * 8 * 7 = 65
8 * 7 * 6 = 50
7 * 6 * 5 = 37

Find
6 * 5 * 4 = ?

The cream is heavier than Milk. True or False?

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

When we see 2 but call 10?