# ACT Math : How to use scientific notation

## Example Questions

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### Example Question #2 : How To Use Scientific Notation

What is the result when ,, is rounded to the nearest thousand and then put in scientific notation?

Explanation:

First, when we round to the nearest thousand we get 5, 679, 000 since we round up when the next digit is greater than 5.

Then, to put it in scientific notation, we arrange the digits so that a decimal point creates a number between 1 and 10. We get 5.679.

Then, we want the exponent of the 10 to be the number of times the decimal needs to move to the right. This is 6 times.

Thus, we get our answer.

### Example Question #3 : How To Use Scientific Notation

What is  in scientific notation?

Explanation:

In order to write a number in scientific notation, you must shift the number of decimal places to get a number in the ones place.

Since the original number is a decimal, the exponent will need to be negative. This eliminates three answer choices.

In order to get  into scientific notation with '5' in the ones place, you must shift the decimal over seven places.

Therefore, the final answer in scientific notation is .

### Example Question #11 : How To Use Scientific Notation

Which of the following is equal to ?

Explanation:

For this, you can handle the s separately from the coefficients.  The s easily cancel:

Now, handle the coefficients like they are a separate fraction:

Notice, though, that :

Now, you need to get this into scientific notation for your answer.  It is easiest ot think of it like this:

### Example Question #12 : How To Use Scientific Notation

Simplify .

Explanation:

The easiest way to work with a large number like this is to combine the  factors and then the other coefficients. After that, you will have to convert the number into scientific notation to match the answer:

Combine the powers of :

Next, combine the other coefficients:

Now, rewrite the leading number like this:

Thus, you get:

### Example Question #13 : How To Use Scientific Notation

is equal to which of the following?