# Revision history [back]

You can do something like:

sage: a = 3 * units.length.kilometer() / units.time.hour() + 12 * units.length.meter()/units.time.second()
sage: a.convert()
77/6*meter/second


But be careful that the current units system is able to add incompatible units and also forget the unit when some terms cancel, see for example this ask question.