In this study, the research results up to now on original word form and its meaning of Korean number words hana, dul, ..., yeol are looked out from math-historically. In fact, finding out original word form and its meaning of hana, dul, and set(ses) may not be possible in the respect of history of mathematics. There might have been a gap between set(ses) and net(nes), and between net(nes) and daseot(daseos). Original word form and its meaning of hana, dul, set(ses), and net(nes) must be found out in different aspect from those of daseot(daseos), yeoseot(yeoseos), ..., yeol. There might have been a gap between yeoseot(yeoseos) and ilgop(ilgob). Coining number word mechanism for ilgop(ilgob), yeodeol,(yeodeolb) and ahop(ahob) might have been same each other. There might have been a gap between ahop(ahob) and yeol. The research results up to now have not paid attention to this gaps sufficiently. But according to history of mathematics, there must have existed several gaps.