The point of reference is 60, and the thought underlying the words may probably be expressed by the paraphrases, "1 on the third score, 2 on the third score, 3 on the third score," etc.

Similarly, 61 is 1 on the fourth score, 81 is one on the fifth score, 381 is 1 on the nineteenth score, and so on to 400.

At 441 the same formation reappears; and it continues to characterize the system in a regular and consistent manner, no matter how far it is extended.[64] The Yoruba language of Africa is another example of most lavish use of subtraction; but it here results in a system much less consistent and natural than that just considered.

Here we find not only 5, 10, and 20 subtracted from the next higher unit, but also 40, and even 100.

For example, 360 is 400 - 40; 460 is 500 - 40; 500 is 600 - 100; 1300 is 1400 - 100, etc.