450,000 = 4.5 x 100,000

100,000 = 10⁵(exponent is equal to the number of zeros)

450,000 = 4.5 x 10⁵

To determine this answer, move the decimal point in 3.0147 until you get 3,014,700,000 (9 places). There are 9 decimal places after the decimal point.

Slide the decimal point to the left as many places as you need to make a number between 1 and 10. Multiply that number by 10 to the power of however many decimal places you moved the decimal.

We want to move the decimal point to the place just after the first non-zero number, in this case 6, and then drop all of the non-significant zeros. We need to move the decimal point five spaces to the right, so our exponent should be negative. If the decimal had moved left, we would have had a positive exponent.

In this case we get 6.009 * 10^–5。

We need to convertinto a number of the form。

The trick is, however, figuring out what应该是。当你将十进制效果t to theright, you need to make the decimal negative. (Note, though, when you multiply by a negative decimal, you moveto the left。We are thinking in "reverse" because we are converting.)

Therefore, for our value,。So, our value is:

The easiest way to do this is to convert each of your answer choices into scientific notion and compare it to。

For each of the answer choices, this would give us:

(Which is, thus, the answer.)

When you convert, youaddfor each place that you move to theleftandsubtractfor each place you move to theright。(注意,这是相反的你做什么时you multiply out the answer. We are thinking in "reverse" because we are converting.)

This is a bit of a scientific notation application test.

Becauseis in the ones place,, and becauseis in the hundredths place,。

From there, it becomes self-explanatory:

。

Remember to take care that you do not giveorinstead of。

Define variables as x = number of crayons and x + 2 = number of notebooks

To find out how much she spent, we subtract her change from what she paid with: 10.00 – 1.05 = 8.95

Then we need to solve the problem cost of notebooks plus the cost of crayons equals the total cost.

1.25(x + 2) + 0.90x = 8.95 and solving for x gives 3 crayons and 5 notebooks

To add decimals, first add zeros to the necessary terms so they all have the same number of places to the right of the decimal point.

Now, temporarily drop the decimal and add the numbers as if they were whole numbers.

Finally, add the decimal place back in, in the same place you removed it from. In this case, we originally modified our numbers so they all had 3 numbers to the right of the decimal, so we will add the decimal back to the exact same place. Thus, our answer is: