Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

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

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

I am an odd number. Take away a letter and I become even. What number am I?

What is next number in the pattern below:

131 517 192 123 ?

Using Only Five 5's and any mathematical operator make sum as 37

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

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?