To provide an abacus for preventing a view of unnecessary visual information so as to easily see the arrangement of beads on the abacus even in circumstances in which it is hard to read the arrangement of the beads on the abacus placed on a grained desk, a textbook with many characters and numbers written thereon, or the like when calculating by using the abacus.

An abacus with a matt and solid color baseplate comprises a solid color baseplate made of a matt material having lightness and chroma saturation different from those of a color of the beads on the abacus so that a pattern of a desk under the abacus or characters on a textbook are not seen from around the beads to be read.