How do you write 300,000,000?

Hint: We are given a number that is written in standard form and we have to convert it into scientific notation so we must know what scientific notation is. Scientific notation is defined as the method of expressing too large or too small numbers in the decimal form for a convenient expression. In scientific notation, a number is written as a product of a number lying between 1 and 10 and a power of 10. An example of scientific notation is $N \times {10^m}$ where N lies between 1 and 10 and involves only significant figures.

Complete step by step answer:
For writing a number in scientific notation we divide and multiply the given number with a power of 10 such that the power is equal to (total number of digits – 1), this way the decimal point is placed after the first digit. Now, the scientific notation should contain only significant figures so the digits after the decimal point are rounded off.
 300,000,000 can be rewritten as $3 \times 100000000$ .
Now, $100000000 = 10 \times 10 \times 10 \times 10 \times 10 \times 10 \times 10 \times 10$ that is $3 \times 100000000$ is equal to the product of 3, and 10 multiplied with itself 8 times, so it can be written as –
$3 \times 100000000 = 3 \times {10^8}$
Hence the scientific notation of $300,000,000$ is $3 \times {10^8}$ .

Note: We simply multiply the decimal number with the power of 10 for converting the scientific notation into standard form, in the given question, while finding the scientific notation, we see that there is only one significant figure so no decimal will be involved, thus the calculation is easy. This way we can solve similar questions.