\label{Significant_Figures}
A \textbf{significant figures} specification tells the system how many significant
figures there are in the problem, as either a single number, e.g. 3, or a range of
acceptable values, expressed as \textbf{min,max}. The system will check to
make sure that the student's answer contains this many significant digits,
useful in many scientific calculations. For example, if the computer answer is {}``1.3'',
and the problem requests three significant digits, specified by (entered without quotes) 
{}``3'',  the system will require the students to type {}``1.30'',
even though numerically, {}``1.3'' and {}``1.30'' are the same. A significant
figure specification of (entered without quotes) {}``3,4'' means both {}``1.30'' and {}``1.300''
are acceptable. The significant figures field can be omitted if you do 
not want to constrain the number of significant digits in the student answers.

Note that care must be used when generating and formating computer answers.
You must assure that the specified answer format provides for enough significant digits.
To test the formatted answer, LON-CAPA converts the computer answer,
as generated in the script block, according to the
format attribute in the numericalresponse tag.
Then LON-CAPA separately applies that number of significant
figures to the computer answer, and if that result
falls outside the range specified in the significant digit parameter, 
it "grades" the computer answer as SIG\_FAIL (i.e., not correct). This helps assure
that you have enough significant digits in the formatted answers you display to the students.
It is a good idea to use the problem testing environment to test plenty of different
randomizations to make sure that your format and sig digits parameters are compatible.

