Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

How do you go from 98 to 720 using just one letter?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

I have two coins.
* One of the coins is a faulty coin having a tail on both sides of it.
* The other coin is a perfect coin (heads on side and tail on other).

I blindfold myself and pick a coin and put the coin on the table. The face of the coin towards the sky is the tail.

What is the probability that another side is also tail?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?