To add numbers on an abacus, you manipulate the beads on the rods, moving them towards the center counting beam to represent increased values.
An abacus consists of a frame, rods, and beads. A horizontal beam separates the beads into two sections: the upper section contains "heavenly" beads (typically one per rod), and the lower section contains "earthly" beads (typically four per rod). The center beam is where beads are moved to register their value.
- Heavenly beads: Each heavenly bead, when moved towards the center beam, typically represents a value of 5.
- Earthly beads: Each earthly bead, when moved towards the center beam, typically represents a value of 1.
Addition involves moving the appropriate number of beads towards the beam on the relevant rod (representing ones, tens, hundreds, etc.).
Abacus Addition: A Simple Example (Adding 5 and 3)
Let's use a simple example, similar to the one shown in the referenced video, to illustrate how to add 5 and 3 on an abacus rod:
- Start with a cleared abacus: All earthly beads should be away from the center beam (down), and all heavenly beads should be away from the center beam (up).
- Represent the first number (5): On the chosen rod (e.g., the units rod), move one heavenly bead downwards towards the center beam. This bead now registers a value of 5.
- Add the second number (3): To add 3, you need to move beads representing a value of 3 towards the center beam on the same rod. Since earthly beads represent a value of 1 each, you will move three earthly beads upwards towards the center beam. As stated in the video, "In order to add five and to add three. We will move three earthly beads towards the center beam. One two three".
- Read the result: Now, count the value of the beads touching the center beam on that rod. You have one heavenly bead (value 5) and three earthly beads (value 1 each). The total value is 5 + 1 + 1 + 1 = 8. "This is 5 and this is 3. 5 plus 3 is equal to 8."
This demonstrates a fundamental principle of abacus addition: increasing the number displayed on a rod by moving beads towards the center beam.
Basic Bead Values
Here's a quick look at bead values when touching the center beam:
| Bead Type | Location Relative to Beam | Value |
|---|---|---|
| Heavenly | Moved Downwards | 5 |
| Earthly | Moved Upwards | 1 |
By combining the values of beads touching the beam on a rod, you get the number represented on that rod. Adding involves moving more beads towards the beam to increase the rod's value.
