But as Dr.Boas was engaged in active work among them for three years, we may conclude that the Eskimo has an arithmetic but little more extended than that which sufficed for the Australians and the forest tribes of Brazil.

Early Russian explorers among the northern tribes of Siberia noticed the same difficulty in ordinary, every-day reckoning among the natives.

At first thought we might, then, state it as a general law that those races which are lowest in the scale of civilization, have the feeblest number sense also; or in other words, the least possible power of grasping the abstract idea of number.
But to this law there are many and important exceptions.

The concurrent testimony of explorers seems to be that savage races possess, in the great majority of cases, the ability to count at least as high as 10.

This limit is often extended to 20, and not infrequently to 100.