abacus
part of speech
noun (an abacus; plural abacuses or abaci)
meaning for a pupil
1) An abacus is a frame with rows of beads that slide along wires or rods, used for counting and doing sums. tree →
2) In buildings, an abacus is the flat slab on top of a column (architecture word). tree →
sense in the lessons
In maths lessons, the abacus helps children see place value: each row is a place (ones, tens, hundreds), and moving beads shows adding, taking away and carrying. In history, abacuses were used in ancient Mesopotamia, Greece, Rome and China; the Chinese suanpan and Japanese soroban are still used. Phrases: «count on an abacus», «move the beads».
examples
- We used an abacus to add 27 and 15. tree →
- On the abacus, the top row shows hundreds and the bottom row shows ones. tree →
- Some children in Japan learn very fast mental maths with a soroban abacus. tree →
- The abacus was used long before calculators. tree →
- Move three beads to the left to add three. tree →
- My little brother counts the coloured beads on his toy abacus. tree →
note
Plural: abacuses (most common) or abaci (formal). Say «AB-a-kus», stress on the first syllable. Maths: on a place-value abacus, each bead on the tens rod is worth 10, so 3 beads on tens and 4 on ones = 34; ten beads on one row are swapped for one bead on the next row up (carrying).
Trees and pragmatics
Every meaning and example of «abacus» parsed by Mova, each sentence with its dependency tree and frames.