Numerical Response problems are answered by entering a number and an optional
unit. For instance, a numerical response problem might have an answer of
2*m*/*s*^{2}. Formula Response problems are answered by entering a mathematical
formula. For instance, a formula response problem might have an answer
of *x*^{2}+11. The answer may be in any equivalent format. For instance,
for *x*^{2}+11, the system will also accept *x***x*+11 or *x*^{2}+21-10.