Can you replace the question mark with the correct number in the below table sequence?

You have four chains. Each chain has three links in it. Although it is difficult to cut the links, you wish to make a single loop with all 12 links. What is the fewest number of cuts you must make to accomplish this task?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

There is a unique number which when multiplied by any number from 1 to 6, we will get the new number that contains the same digits only.

Can you find that number?

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

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

Two fathers and two sons decided to go to a shop and buy some sweets upon reaching. Each of them bought 1 kg of sweet. All of them returned home after some time and found out that they had 3kg of sweets with them.

They did not eat the sweets in the way, nor threw or lose anything. Then, how can this be possible?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

How many letters are in the alphabet?