abacuses

n.

a tablet placed horizontally on top of the capital of a column as an aid in supporting the architrave

a calculator that performs arithmetic functions by manually sliding counters on rods or in grooves

1. The museum displayed a collection of ancient abacuses.
   博物馆展示了一系列古老的算盘。
2. He learned to use an abacus at a young age.
   他在很小的时候就学会了使用算盘。