How do these compare with other packages? We use DERIVE (inexpensive, from Soft Warehouse in Honolulu). DERIVE also includes graphics. It's weakest points are (1) occasional dumb pursuit of integration by parts (2) inability to do standard floating point calculation (would be 100x faster). The learning feature you mentioned sounds unusual. Karl Irikura Natl. Inst. of Standards & Tech., Chem. Kinetics & Thermo. irikura \\at// enh.nist.gov