Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

What kind of band never plays music?

If 21x = 79x, what is the value of x?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

Find the missing letter in the last circle logically in the given below picture.

You visit a home for specially-abled children on the occasion of Christmas where you meet with 50 children. You have a box of chocolates containing 50 chocolates exactly.

What if you were asked to one chocolate to each child in a manner that one chocolate still remains in the box? Is it possible?