Lesson · L1

One-Rod Number Pairs

mixed-operations 14 min child, adult 数 九
L1Level
mixed-operationsSkill
14mTime
child/adultAudience
First Subtraction on One RodPrerequisite
Best for

Best for guided progression in this stage of practice.

1. Read the core idea 2. Study the worked example 3. Practice the related drills

Core idea

Train easy one-rod pairs so direct movement feels clean before complements become necessary.

View progress

Objectives

  • Recognize friendly one-rod pairs that change shape but stay on the same rod.
  • Build cleaner direct-add and direct-subtract confidence.

Reusable visual engine

Worked visual for One-Rod Number Pairs

Value 9 · 九

Step 1

9

Step 2

6

Before complements, there are many friendly number pairs that can still live calmly on one rod.

Core idea

Pairs like 6 + 3 or 9 - 3 are useful because they change the bead shape, but the whole result still stays visible on one rod.

Practice habit

Read the starting value first, then the final value, instead of treating the middle movement as the whole problem.

Common mistakes

  • Moving beads correctly but failing to re-read the final rod.
  • Counting only the latest move and forgetting the whole value.

Next step

Continue with guided practice

Use practice mode for immediate repetition, or open worksheets for denser drill sets tied to this level and skill.

Previous lesson

First Subtraction on One Rod

Learn subtraction as careful removal, not rushed guessing.

Next lesson

Complements to Five

Use number pairs to move more efficiently on the soroban.

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