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# how to prevent a right answer from being marked as wrong.

i got the correct answer of -7/9. The answer box said decimals accepted, or something along those lines. I put down .7777 and got a wrong answer message along with the message, the correct answer is .777......... Now the correct answer given had something like 30 decimal places. It is upsetting to solve a problem correctly and have it graded as incorrect for something like this. I would prefer it if the answer box said something like "Fractions accepted.", or show answer to 30 significant decimal places".

Calvin edit: The answer that you wrote was "-777", instead of "-0.777". There was a missing decimal point, hence you were marked wrong.

Note by Michael Enright
2 years, 9 months ago

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You're Right. Even I don't like it.

The Current Format accepts answers within 2% of the correct answer if it's a decimal answer, and the exact number if it's a integer.

Still, your answer was within range, and should, hence, have been accepted.

- 2 years, 9 months ago

yes, you are right this troubles me sometimes also. We want help from the staff @Calvin Lin .

- 2 years, 9 months ago

Calvin, Thanks for clearing this up.

- 2 years, 9 months ago

Updated: I looked at your recent problems. I believe you are referring to a Calculus practice problem where you are given $$f(x) = \frac{1}{ x g(x) + 3 }$$ and asked to find $$f' (0)$$.

The correct answer is $$-0.77777...$$, and we accept a $$\pm 2 \%$$ range of answers (and so 3 sig fig would be sufficient). Your entered answer was $$-777$$, without a decimal point. Hence it was marked incorrect.

Michael, can you link me to the problem? If you file a report on the problem, I can take a look at it from there.

By right, you should be graded correctly if the correct answer is 0.777777777.... and you entered it in as 0.777.

Staff - 2 years, 9 months ago

The correct answer was -7/9, which I got. At this point I believe I converted the answer to decimal correctly and then one of at least three sings happened. I either forgot the negative sign, forgot the decimal, or only entered three digits when the when the problem called for four. Now I'm very careful to follow the formatting for the answer that is called for in the problem. I really don't care about the points. I'm just having fun attacking the problems. I think we should just forget it but I appreciate your offer of help.

- 2 years, 9 months ago

I know it often becomes a trouble and it is really irritating you get your answer wrong for the reason you have entered it more accurately.But it is actually the responsibility of the problem creator to ensure that either to specify the accuracy up to which he expects the answer or make the answer an integer value (For example by using floor or ceiling functions.)

- 2 years, 9 months ago

Thank you for your reply. So I guess the author of the problem entered the correct answer but now that I think about it the answer given with the problem had a string of sevens for maybe 20 decimal places and then began a string of other digits besides seven. However, the answer of -7/9 equals -.77777 repeating sevens to infinity so the answer as stated in the problem is wrong.
Now I'm getting too picky. This is all in fun so I'll just let it go and have fun today looking at some more good problems. By the way, it was a fun and interesting problem.

- 2 years, 9 months ago

For reasons like you mentioned, decimal answers are accepted in a $$\pm 2 \%$$ range. You do not need (nor are expected to) match the degree of accuracy on a decimal answer. This applies especially in cases where constants are used, e.g. $$\pi \approx 3.1415 , e \approx 2.71828 , \frac{1}{9} \approx 0.1111$$.

Staff - 2 years, 9 months ago