According to Lounge,[1] the Yoruba language has a rather elaborate vigesimal (base-20) numeral system that involves both addition and subtraction and multiplication.
Multiples are also very important in the numerical system for example the number 60 is ọgọ́ta which literally means three twenties (ogún = 20, ẹ̀ta = 3).
Units apart from the fives are generally transparent: oókànlélógún 'twenty-one', eéjìdínlọ́ɡbọ̀n 'twenty-eight', etc.
There are also more recent decimal forms for the thousands: 2,000 ẹgbẹ̀rún méjì 'thousand twice', 3,000 ẹgbẹ̀rún mẹ́ta 'thousand thrice', etc., as well as additive forms for the fives, due to the influence of English.
Numbers higher than 20,000 also tend to be transparent: 40,000 is ẹgbàawàá lọ́nà méjì '20,000 two times'.