Abacus

Abacus. Used in China and Japan, even today. There are 2 styles. Chinese and Japan style.

Chinese style abacus has 2 rows at top, and 5 rows at bottow. This allows use with a hexadecimal numeral system (or any base up to 18).

The default position is away from the middle horizontal bar. Each bead positioned close to the horizontal bar counts a value. For bottom section beads, each bead counts as 1. For top section beads, each bead counts as 5.

Japanese Style Abacus

The Japanese style abacus has 1 row at top, 4 rows at bottom. For top section beads, each bead counts as 5. For bottom section beads, each bead counts as 1.

When i was in school aged around 9 (that's 1970s), abacus is still taught in school at Taiwan. And, there are TV shows of competition between students using abacus versus students using electronic calculator.