What does this below rebus puzzle mean?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

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

The centre of the third figure is empty. What digit should fit inside?

What does this mean?

CCCCCCC

I am lying and I always lie. Tell me whether I am lying or telling the truth.

Using eight eights and addition only, can you make 1000?

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?