Expert: Bobby Soltani - 7/17/2005

Question
Hello:

I read in a textbook the following:

"Divide 4 by 11, correct to the nearest thousandth."

Answer: 0.364

What does "correct" indicate in the above?

I thank you for your answer.

Answer
Hi,

The term correct is synonymous with the word "round."  When you want to express a number, you may not want to write out the entire number because only a certain amount of accuracy is needed.  For instance, if I asked you what time it is, you wouldn't say 10:40 and 18 seconds.  You would simply say 10:40.  You could say that you rounded or corrected to the nearest minute.  

When working with decimals, the trick is to look at the number to the right of the last digit that you want to keep, and if it is 5-9, then you increase the last digit you want to keep by one.  If the number to the right of the last digit is 0-4, then you just drop the numbers to the right and leave the last digit the same.  Here are a couple of examples.

1.
6.574 to the nearest hundredth.
The hundredth's place is a 7, and the number to the right is a 4.  Since 4 is in the range 0-4, we just drop it and leave the 7 the same.  So, the answer is 6.57.

2.
5.2845213 to the nearest thousandth.
The thousandth's place is a 4, and the number to the right is a 5.  Since 5 is in the group 5-9, we drop the numbers and add 1 to the 4 to get
5.285

Your problem:
4/11 = 0.3636363636363....
The thousandth's place is a 3, and the number to the right of that is 6.  So we correct the 3 up to a 4.
0.364

Let me know if you have any questions.

Bobby