Question

Which number is not in scientific notation?

three point four times ten to the negative first power

zero point four times ten to the fifth power

one point nine eight times ten to the negative twentieth power

eight times ten to the twelfth power

Answer 1

Here are your choices:

A. 3.4 * 10^-1

B. 0.4 * 10^5

C. 1.9 * 10^-20

D. 8 * 10^12

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In my experience, scientific notation never has decimals without a whole number.

Take a look at B.

It's 0.4 * 10^5

You see how 0.4 is a decimal,
but it doesn't have a whole number?

(Unlike 3.5, which is a decimal that DOES have a whole number: 3)

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The better way to write 0.4 would be.....

4 * 10^-1

Or... "four times ten to the negative first power."

Answer 2

By the way, this section is for Spanish questions.

You're welcome to post questions like this in the Mathematics section.

You'd probably get help a lot sooner that way, since there are thousands of people who are always in there.