What does this simple rebus mean?

You have a thousand Re. 1 coins with you. You have ten bags with you and you can put any number of coins in each of the bags. The condition is that if someone asks you for any amount between 1 and 1000, you must be able to give that amount by just giving the bag (you are not allowed to open the bag and give coins).

How will you do it?

My sock drawer has 26 blue socks, 13 pink socks, 33 green socks, and 12 red socks, how many socks would I have to pull out in the dark to be sure I had a matching pair?

Can you tell a 3D object that has just two surfaces?

You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.

What does this mean?

CCCCCCC

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

What does this rebus means ?

PROG WORKRESS

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?