# Video: Expressing Numbers in Scientific Notation

Express 25 in scientific notation.

01:33

### Video Transcript

Express 25 in scientific notation.

The format for a scientific notation looks like this: 𝑎 times ten to the 𝑏, where 𝑎 is a factor greater than or equal to one, but less than ten and 𝑏 is a positive or negative power of ten. We start with 25 and then we add a decimal and a zero. Here, we haven’t changed the value of 25; we’ve just written it in a different format.

Now I want a factor that’s greater than or equal to one, but less than ten. And I find that by moving my decimal place. I’ve moved my decimal place one time to the left. If we move our decimal place to the left, we will end up with a positive exponent. If we move our decimal point to the right, we’ll end up with a negative exponent.

We moved our decimal point one time to the left, which means that we will have a positive power of ten and it will be one. 2.5 times ten to the first power is 25 written in scientific notation. You could check that this is true by multiplying 2.5 times ten to the first power or just ten and 2.5 times ten equals 25.