Round 18.2044986022 to the nearest hundred-thousandth.

The answer is 18.2045

Step-by-step explanation:

In order to determine the rounded number, we have to know about the notation numbers. In any number, every digit has a unique notation depending on his place.

I have attached an image that shows some notation numbers. We can see that the hundred-thousandth place is the fifth digit after the decimal point.

Then we have to see the next digit. If the digit is greater or equal than 5, we have to increase in one unit the number in the place we want to round. If not, the number does not change.

In this case:

Fifth decimal number is 9

Sixth decimal number is 8, so we have to increase 9 by 1.

Finally the number is 18.2045

a = 11 : 4

b = 38

c = 1 for every 6