[LON-CAPA-users] Making something out of nothing with preprocessing?

[Mills, Douglas G]

Hi All,

There are times, such as filling in coefficients to balance a chemical equation, when the best answer would be no answer at all. Requiring students to put 1 as the coefficient of O2 in the reaction

"2H2 + O2 -> 2H2O"

when they are presented with [numericalresponse]H2 + [numericalresponse]O2 -> [numericalresponse]H2O because if they don't Lon-Capa will not process the answer because "not all answers were submitted" is an artificial concession to the LMS that I'd like to avoid.  I had thought maybe with preprocessing I could instruct students to leave a text field blank -- as such an equation would normally be written -- when the coefficient is 1 and then preprocess and insert a 1 for the case where the textfield is empty so that Lon-Capa is getting an answer without the artificial exercise of the student putting in a coefficient of 1, but that does not seem to be working.  Should that be possible and I'm just going about it the wrong way?   Any other ideas on how to address this besides instructing students to give 1 as the answer?

Thanks!

Doug

Douglas Mills
Director of Instructional Technology
Department of Chemistry
University of Illinois

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