CS100 Basic Computing
Chisenbop

NEW Chisenbop tutorial on the way!!!

I wrote the page you are looking at several years ago, and forgot all about it. During the last few months, I began getting emails about chisenbop from all over the world. It was only then that I remembered writing this page as one of my very first web pages oh so many years ago. I am a little embarrassed that it is one of my most popular pages. It is incomplete and sloppy.

Here is another site in progress, which uses digital images and javascript to illustrate the process a little more clearly. (I hope) It is still very much a work in progress, but I do encourage you to experiment and enjoy it.

The new chisenbop page

-Andy Harris

Using your fingers as an analog computer

  1. Background
    1. Korea
    2. Similar technique to abacus, soroban
    3. Ancient technique
  2. Counting
    1. Each finger has two positions:
      1. Up - off table or hidden
      2. Down - On table or showing
    2. Right hand:
      1. Each finger counts as 1
      2. Thumb counts as 5
        [Graphic Chis1: 0-9]
    3. Left Hand:
      1. Each finger counts as 10
      2. Thumb counts as 50
        [Graphic Chis2: 10-90]
    4. Two Digit Numbers:
      1. Combine left hand (10s digit) with right hand (1s digit)
        [graphic Chis3: 31, 55, 68, 99]
  3. Simple Adding
    1. One digit
      1. Right hand only
      2. Make first digit
      3. Count out second digit
      4. Read response
      5. Example: 2+2
        [Graphic Chis4: 2 + 1...2=.....4]
    2. Two digit
      1. Add tens on left hand, then ones on right hand
      2. Example: 61 + 23
        [Graphic Chis5: 61 + 20 + 3 = 84]
  4. Simple Subtraction
    1. One Digit
      1. Make first number, pull away appropriate numbers
      2. Example: 4-1
        [Graphic Chis6: 4 - 1..2..3 = 1]
    2. Two Digits
      1. Left hand then right hand
      2. Example: 37 - 15
        [Graphic Chis7: 37 - 10 - 5 = 22]
  5. Adding "around the corner"
    1. Going from 4 to 5 (or 40 to 50)
      1. Put down thumb
      2. Pick up other fingers
      3. Example: 3 + 4
        [Graphic Chis8: 3 + 1..2..3..4 = 7]
    2. Going From 9 to 10 (19 to 20, etc)
      1. Add ten to left hand
      2. Pick up all fingers on right hand
      3. Example: 5 + 6
        [Graphic Chis9: 5 + 1..2..3..4..5..6 = 11]
    3. Both (Whew!)
      1. Just combine methods
      2. Example: 32 + 49
        [Graphic Chis10: 32 + 10..20..30..40 + 5..6..7..8..9 = 81]
      3. Example: 49 + 22
        [Graphic Chis11: 49 + 20 + 1..2] -or-
        [Graphic Chis12: 50 + 20 + 2 - 1]
  6. Subtraction with borrowing
    1. Fingers
      1. Subtract 10, add difference between number and 10
      2. Example: 41 - 9
      3. (Remember, - 9 is - 10 + 1
        [Graphic Chis13: 41 - 10 + 1]
    2. Thumbs
      1. Subtract 5 (or 50), add the difference
      2. Example: 6 - 3
      3. (-3 = - 5 + 2)
        [Graphic Chis14: 6 - 5 + 2]
    3. Both
      1. Combine concepts
      2. Example: 50 - 21:
        [Graphic Chis15: 50 - 20 - 10 + 9]

Comparison with how computer works

  1. Similarities
    1. Basically only two values -on/off
    2. Combination of simple values to make larger numbers
    3. Place - holding
    4. Limited maximum value
    5. Numbers represented artificially (fingers or electrical)
    6. Characters could be represented by numbers
  2. Differences
    1. Chisenbop not true binary
    2. No Five register in binary
    3. Chisenbop cannot deal with instructions, only numbers