Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

What does the below rebus riddle means?

Find the number of squares in the below picture