Extra: adding and subtracting on the abacus
Add and subtract 2-digit numbers by moving beads on an abacus. Exchange ten ones beads for one tens bead, and back.
- Germany: grade 2
- Iran: grade 2
- Afghanistan: grade 2
- Syria: grade 2
- Palestine: grade 2
- Ukraine: grade 2
- Russia: grade 2
Guide
This is an extra studio. In Afghanistan, children in grade 2 add and subtract on the "chot", a simple abacus.
The right rod is the ones, the left rod is the tens. Each bead on the tens rod is worth 10.
If the ones rod has 10 beads or more, press ← 10: ten beads come off and one bead goes on the tens rod.
If there aren't enough ones beads, press 1 →: one tens bead comes off and ten beads go on the ones rod.