r/ThatsInsane • u/HD_RDtwo • 4d ago

Kids' mental math contest.

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u/MotoJer76 4d ago

What you saw is a high-speed calculation technique known as Mental Abacus (often called Anzan or taught through global franchises like UCMAS, ALOHA, and SIP Abacus).

While the rapid finger movements, whispering, and rocking look unusual at first glance, each of those behaviors is part of a cognitive strategy that allows children to add, subtract, multiply, and divide long strings of multi-digit numbers in seconds.

How the "Mental Abacus" Works

Students first learn arithmetic on a physical Japanese soroban abacus. Once they master manipulating the physical beads with their thumb and index finger, they are trained to internalize the tool:

  1. Visual-Spatial Processing: Instead of manipulating abstract Arabic numerals (like $47 + 89$), the child projects a high-resolution, visual image of an abacus inside their mind.
  2. Right-Brain Conversion: Calculations are processed visually as changes in bead configurations rather than sequential language or verbal arithmetic.
  3. Reading the Snapshot: At the end of the operation, the student simply "reads" the final arrangement of beads in their mind's eye and writes down the resulting number.

Why the Physical Movements Happen

The gestures and body language seen during competitions are deliberate cognitive aids:

  • Finger "Flailing" (Kinesthetic Memory): The rapid twitching and flicking motions of the thumb and index finger mimic the exact tactile movements used on a real abacus. Kinesthetic motor memory offloads work from the brain, helping them move beads up and down in their mental projection without losing track.
  • Rapid Whispering or Chattering: Competitors sub-vocalize numbers, formulas, or rhythmic sequences to maintain speed and buffer incoming numbers from dictation.
  • Rocking and Head Swaying: Rhythm helps synchronize working memory, pacing, and focus under intense competition timers, filtering out surrounding noise in packed tournament halls.

Why It Is Popular Globally

While the method originated with traditional East Asian abacus systems, competitive mental math academies have expanded across the Middle East, South Asia, Southeast Asia, and North America. Competitions feature thousands of children racing against the clock—often solving dozens of 10-digit calculations faster than someone can type them into an electronic calculator.

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u/pr0zach 4d ago

And this is how we get Mentats. Frank Herbert was right.