In the modular representation theory of the symmetric groups (and related topics), the abacus representation of partitions (introduced by Gordon James) plays an important role. Using the abacus, there are nice combinatorial algorithms for computing representation theoretical information.


The following is from the page Etymologically speaking...." (recommended for lovers of linguistics!)


Abacus
Comes from the Greek word abax, which means "sand tray." Originally, columns of pebbles were laid out on the sand for purposes of counting. See calculate and exchequer.

Algorithm
This term, which means "rules for computing" in English, comes from al-Khowarizmi (Try saying it fast), an Arab mathematician living around A.D. 825 who completed the earliest known work in arithmetic using Arabic numerals. He was the first to establish rules for adding, subtracting, multiplying and dividing with the new Arabic numerals.

Calculate
Comes from calculus, the Latin word for pebble. In Ancient Rome, as in Ancient Greece, pebbles were used in the abacus or counting frame in order to carry out basic arithmetic computations (see abacus and exchequer).

Exchequer
The Moors introduced the Abacus to Europe so that the Europeans could multiply, and the monks spread this device throughout Europe. In Britain, it was used but with their own twist to it: they used a checkboard and checker-like pieces (rather than the usual rods and beads) -- and this British version gave rise to the "exchequer" in "Chancellor of the Exchequer."