--- loncom/html/adm/help/tex/Numerical_Response_Units.tex	2004/05/17 14:37:55	1.3
+++ loncom/html/adm/help/tex/Numerical_Response_Units.tex	2013/07/05 18:30:40	1.5
@@ -1,8 +1,14 @@
 \label{Numerical_Response_Units}
 
 Numerical Response problems can require units. In the problem editing form,
-place the desired unit in the \textbf{Unit} field. For information about
-what units the system accepts, see \ref{Physical_Units}.
+place the desired unit in the \textbf{Unit} field. A complete list of 
+units is in the section \ref{Physical_Units}.
 The computer will accept the answer in any of its accepted unit formats.
 For example, if the answer to a problem is {}``1ft'', the computer will
 accept {}``12in'' as correct.
+
+Additional units can be defined using the ``customunits'' parameter, which is a comma-separated list of unit conversions. For example
+\begin{verbatim}
+peck=2*gallon,bushel=8*gallon,gallon=4.4*L
+\end{verbatim}
+would define the new units peck, bushel, and gallon. The last entry in a conversion chain always needs to be a unit that LON-CAPA already supports.