Phenomenal Business Acumen of Yoruba Women

Before the arrival of the British on the shores of Yorubaland and the eventual colonisation of the country from 1861 to 1960, Yoruba women held sway in business (they still do these days to some extent).

They were the main participants in the marketplace hence the existence of chieftaincy titles like Ìyálọ́jà (Mother or custodian of the market) and Ìyálájé (Mother or custodian of the economy).

It is a known fact that Mathematics/Arithmetic is the language of business and trade. In a society where orality eclipsed literacy, the only way to become an astute businesswoman was to be well versed in the art of mental Arithmetic. Being able to perform complex arithmetic mentally without any computing device like abacus (used then in Europe and Asia) was a monumental feat but this was helped by the vigesimal (Base 20) Numeral System developed many centuries ago in the heartland of Yorubaland.
This is best demonstrated using the following examples:

15 = ẹẹdogun (from arun din ogun = five reduces twenty)

16 = ẹẹrin-din-logun (20 - 4) 

17 = ẹẹta-din-logun (20 - 3) 

18 = eeji-din-logun (20 - 2) 

19 = ookan-din-logun (20 - 1) 

20 = ogun 

21 = ookan-le-logun ("one on twenty" = 20 + 1) 

25 = ẹẹdọọgbọn (30 - 5) 

30 = ọgbọ̀n 

35 = aarun-din-logoji (five less than two twenties = (20 X 2) - 5) 

40 = ogoji ("twenty twos") 

50 = aadọta (20 X 3 -10) 

60 = ọgọta (3 X 20, i.e twenty in three ways) 

100 = ọgọrun = orun (20 X 5) 

105 = aarun din laadọfa (20 X 6 - 10 - 5) 

200 = igba

300 = ọọdunrun = ọọdun [20 X (20 - 5)]

315 = orin din nirinwo odin marun [400-(20 X 4)-5] 

400 = irinwo (A big number like an elephant)

2000 = ẹgbẹwa (200 X 10) 

4000 = ẹgbaaji (2 X 2000) 

20,000 = ẹgbaawaa (2000 X 10) 

40,000 = ẹgbaawaa lonan meji (ten 2000s in two ways) 

1,000,000 = ẹgbẹẹgbẹrun (1000 X 1000)

Apart from numbers, there are also fractions (ẹ̀bù)...

Idameji = half
Idamẹta = one-third
Idamẹrin = one-fourth
Idamarun= one-fifth
Idamẹfa = one-sixth
Idameje = one-seventh
Idamẹjọ = one-eighth
Idamẹsan = one-ninth
Idamẹwa = one-tenth
etc.

And there are multiplications...

Ilọpomeji= two times (i.e double)
Ẹrin lọna meji= 4 X 2 (4 in 2 places)
Ẹrin lọna mẹta = 4 X 3 (4 in 3 places)
Ẹrin lọna mẹrin = 4 X 4 (4 in 4 places)
etc.