Abacus glossary

How to use this page

Each term links to the guide where it is explained properly, with pictures. Terms are in alphabetical order.

Terms A to Z

Abacus

A counting frame with beads on rods. Each rod holds one digit, and a bead counts when it is pushed against the central bar. Read more

Anzan

Mental abacus calculation: picturing a soroban and its bead moves in your head instead of using a real one. Read more

Beam

The horizontal bar across the middle of a soroban. Beads touching it count; beads away from it do not. Also called the reckoning bar. Read more

Big friends

A name used with children for pairs of numbers that make 10: 1 and 9, 2 and 8, 3 and 7, 4 and 6, 5 and 5. Read more

Borrow

When taking away and a rod does not have enough, take 1 from the rod on its left first, then add the big friend to the current rod. Read more

Carry

When adding would take a rod past 9, take the big friend away from that rod, then add 1 to the rod on its left. Read more

Clearing

Resetting the soroban so every rod shows 0, with every bead pushed away from the beam. Every calculation starts from a cleared board. Read more

Combined move

Moving the heaven bead and earth beads at the same time with two fingers, as one flick. Used for 6 to 9 and for complements. Read more

Complement

The number that makes a pair add up to 5 or to 10. Complements let you add or take away in one movement when there are not enough beads. Read more

Dividend

In division, the number being divided. It is set on the right of the board. Read more

Divisor

In division, the number you divide by. It is set on the left, four rods away from the dividend. Read more

Earth bead

One of the four beads below the beam on each rod. Each is worth 1 when pushed up to the beam. Read more

Flash anzan

A mental abacus exercise in which numbers appear one at a time and you keep the running total in your head. Read more

Heaven bead

The single bead above the beam on each rod. It is worth 5 when pushed down to the beam. Read more

Little friends

A name used with children for pairs of numbers that make 5: 1 and 4, 2 and 3. Read more

Multiplicand

In multiplication, the number being multiplied. It is set towards the right of the board. Read more

Multiplier

In multiplication, the number you multiply by. It is set on the left, two rods away from the multiplicand. Read more

Partial product

In multiplication, one single-digit times-table answer, added onto the board in its place. Read more

Quotient

The answer to a division. On a soroban it forms in the gap between the divisor and the dividend. Read more

Rod

One of the vertical wires on an abacus. Each rod holds one digit. Read more

Schoty

The Russian abacus, with ten beads on each horizontal wire and no 5-bead. Read more

Soroban

The Japanese abacus, with one bead worth 5 above the beam and four beads worth 1 below it on every rod. Read more

Suanpan

The Chinese abacus, traditionally with two beads above the beam and five below on every rod. Read more

Unit point

A dot on the beam, found on every third rod. Choose one to be your ones rod; the others mark thousands and decimal places. Read more

Unit rod

The rod you choose to hold the ones digit of a number, usually one with a unit point. Read more