Dear colleagues:

God morning. I am working on ancient classification of numbers: abstract numbers and concrete numbers. Also, on classification of concrete numbers in complex numbers and non complex numbers. For instance, complex numbers were "3 years 4 months 15 days" or "43 degrees 18 minutes 17 seconds". Please, could you say me who categorized numbers in abstact numbers and concrete numbers, and the last ones in complex numbers and non complex numbers? What references should I to consult?

Thank yoy for your answer. Regards from Peru

Luis