By Diego Marinho 道 Soroban Dojo Small steps, steady hands · そろばん道場
More routes

Lesson · L5

Mental Soroban Sequences

anzan 24 min child, adult 数 二六
All lessons This level Worksheet
L5Level
anzanSkill
24mTime
child/adultAudience
Building Quotients in DivisionPrerequisite
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

Start mental soroban with short, readable sequences that train stable internal totals before speed becomes the goal.

View progress

Objectives

  • Hold a short running total without relying on a visible worksheet for every step.
  • Read sign changes calmly during short mental sequences.
  • Keep a stable internal image instead of chasing every digit separately.

Reusable visual engine

Worked visual for Mental Soroban Sequences

Value 26 · 二六

Step 1

26

Step 2

18

Step 3

25

Step 4

21

Quick check

Mini checks for mental sequences

  • In 18 + 7 - 4 + 5, which total should be held before the final step?
  • Why is it safer to re-read 21 before adding 5?
  • If you lose the total after a subtraction, what should you rebuild first?

What is 18 + 7 - 4 + 5?

Attempt first, then check.

Mental soroban does not start with speed. It starts with keeping one clean internal image for a little longer than before.

Core idea

In anzan, the question is not only “what is the answer?” It is also:

  • Can you keep the current total clear?
  • Can you survive a sign change without losing the number?
  • Can you re-read the total mentally after each step?

Worked example: 18 + 7 - 4 + 5

  1. Start from 18.
  2. Add 7 to reach 25.
  3. Subtract 4 to reach 21.
  4. Add 5 to reach 26.

Mental rule

For early anzan, use this rhythm:

  1. Read the current total.
  2. Read the next sign.
  3. Apply only one move.
  4. Re-read the new total before continuing.

Do not stack all the operations in your head at once.

Common mistakes

  • Remembering the latest operation but forgetting the running total.
  • Reacting to the next number before confirming the previous result.
  • Letting a subtraction force a full reset of the mental image.

Practice habit

Work in short sequences first. Four calm steps are better training than ten rushed ones.

Next step

Continue with guided practice

Practice this level Open worksheet Mental recall worksheet Review prerequisite

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

Previous lesson

Building Quotients in Division

Extend exact division into stronger quotient-finding habits so the operation feels deliberate instead of lucky.

Best next step: stabilize the prerequisite first Open previous lesson →

Next lesson

Speed Rhythm and Error Checking

Learn how to increase speed while keeping the total stable, the rhythm controlled, and errors small enough to catch quickly.

Best next step: continue while the pattern is still clear Open next lesson →

Related exercises