The total value of all the quarters made in 2014 was 400 million dollars. There are many ways to express this using powers of 10. We could write this as $400 \boldcdot 10^6$ dollars, $40 \boldcdot 10^7$ dollars, $0.4 \boldcdot 10^9$ dollars, or many other ways. One special way to write this quantity is called scientific notation, where the first factor is a number greater than or equal to 1, but less than 10, and the second factor is an integer power of 10

In scientific notation,

400 million dollars

would be written as

$4 \times 10^8$ dollars.

Writing the number this way shows exactly where it lies between two consecutive powers of 10. The $10^8$ shows us the number is between $10^8$ and $10^9$. The 4 shows us that the number is 4 tenths of the way to $10^9$.

A number line, 11 tick marks, 0, 1 times 10 to the power 11, 2  times 10 to the power 11, 3 times 10 to the power 11, 4 times 10 to the power 11, 5 times 10 to the power 11, 6 times 10 to the power 11, 7 times 10 to the power 11, 8 times 10 to the power 11, 9 times 10 to the power 11, 10 to the power 12. Three times 10 to the power 11 to 4 times 10 to the power 11 is zoomed out, to 11 tick marks labeled 3 times 10 to the power 11, blank, blank, blank, 3 point 4 times 10 to the power 11, blank, blank, blank, blank, blank, 4 times 10 to the power 11.

For scientific notation, the "$\times$" symbol is the standard way to show multiplication instead of the dot symbol. Some other examples of scientific notation are $1.2 \times 10^{\text-8}$, $9.99 \times 10^{16}$, and $7 \times 10^{12}$.