What is scientific notation? In 4 paragraphs

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Aswimming pool is a rectangle with semicircles on the end. the rectangle is 12 meters wide and 30 meters long. the diameter and width of the swimming pool are equal. sketch and label an overhead diagram of the swimming pool. find the area of the swimming pool floor.

If you had $1,900,000, how many days would it take you to spend all if you spent $1 a second. (there are 86,400 seconds in a day)