1. A computerized assessment grading method comprising: receiving, by a processing device, an encoded equation-based response to at least one assessment question, said at least one assessment question comprising an equation; decoding, by the processing device, said encoded equation-based response to yield a decoded equation-based response; determining, by the processing device, a grading method selected from a plurality of different grading methods; creating, by the processing device, (i) a syntax tree for the decoded equation-based response and (ii) a syntax tree for at least one solution to the at least one assessment question; determining, by the processing device, whether the decoded equation-based response matches the equation of said at least one assessment question; if the decoded equation-based response does not match the equation of said at least one assessment question, comparing, by the processing device, the syntax trees; and grading, by the processing device, the response according to the determined grading method based on the results of the comparison; wherein said grading comprises awarding a score based on the extent to which nodes of the syntax trees match.