# Suànpán Arithmetic: The Ancient Algorithm
The Suànpán is a bead-frame calculator used for centuries in East Asia. It represents a sophisticated **bi-quinary** system that allows for calculations faster than early digital machines.
### The Architectural Logic
A standard Suànpán has two decks:
- **Upper Deck:** Contains 2 beads. Each represents a value of **5**.
- **Lower Deck:** Contains 5 beads. Each represents a value of **1**.
### Positional Alignment
When beads are moved toward the **center bar**, they are considered "active." A value is "read" by counting the sum of active beads in a column.
### The Zhùsuàn Technique
To add 7:
1. Move 1 upper bead down (+5).
2. Move 2 lower beads up (+2).
3. Total active = 7.
**Task:** In the virtual board below, simulate the addition of $12 + 15$.
Use the logic command: `add(12, 15)`
Current Objective
Learn the ancient Chinese art of rapid calculation and accounting, using the Suànpán bead configuration.
1
Understand the bi-quinary bead system
2
Perform basic addition using the Zhùsuàn technique
3
Map decimal values to physical bead positions
Socratic Mentor
Hello! I'm your Socratic mentor. Stuck on a problem? Tell me what you're thinking, and we'll work through it together.