Which of the following expressions is written in scientific notation? 0.2 × 10^ -5 31.4 × 10^ 4 13 × 10^ 4 1 × 10^ -3

D.

Step-by-step explanation:

We have been given 4 numbers. We are asked to choose the number that is written in scientific notation.  

We know that a number is in scientific notation, when it has two factors such that one factor is greater than or equal to 1 and less than 10 and other factor is a power of 10.  

Upon looking at our given choices, we can see that only option D is the correct choice.

We can see that 1st factor of other numbers is either greater than 10 or less than 1, so they are not in scientific notation.

Therefore, option D is the correct choice.

3/6   and 9/18

step-by-step explanation:

step-by-step explanation:

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