## Lo Shu Activity

### Objectives: [NCTM Standards: Number and Operations and Connections]

1. Students will learn the properties of the Lo Shu magic square.
2. Students will learn the historical background of magic squares.
3. Students will experience the recreational and mathematical aspects of magic squares.

### Materials:

Method 1: If Internet display capabilities are available or students have access to the Web at individual computer stations, the activity can be structured by viewing the story of the Emperor Yu interactively and then continuing with the activity.

Method 2: Prepare overhead transparencies and/or handouts before presenting the activity, including:

For both Methods 1 and 2:

1. Blank paper
2. Blank overhead transparency and pens
3. Rulers

### Procedure:

Relate "Emperor Yu's Story."
Story Questions:
1. Using dots, draw what you think the turtle would look like in the night sky.
2. What is it about the Huang-He (Yellow River) and water that relaxes the emperor?
3. Write a short description of how the turtle got its dots.
4. Emperor Yu didn't understand the number pattern on the turtle's back. Explain in your own words how the position of the numbers makes the square "magic."

Number Questions:

1. What is magic about the arrangement of the numbers in the 3x3 cell square?
2. What is the first number?
3. What is the last number?
4. How many numbers are there?
5. Is any number repeated?
6. What is the sum of the numbers in the1st row? 2nd row? 3rd row?
7. What is the sum of the numbers in the1st column? 2nd column? 3rd column?
8. What is the sum of the numbers on one diagonal? the other diagonal?
With the teacher modeling on the overhead projector, have the students construct a 3x3 grid. Use the drawing of the turtle and write in the grid the numerals that correspond to the configurations of dots on the turtle's back. [The numerals should be positioned in the center of each cell of the grid.]

Draw a dot in the center of each numeral for reference. Using a ruler, connect the dots starting at 1, going to 2, 3... to 9 [refer to Magic Square with lines].

Symmetry Questions:

1. What patterns do you see?
2. If you draw a reference line from the 8 through the 5 to the 2, what symmetrical relationships do you see?
3. Are there any other symmetrical relationships?
4. 5 is in the center of the square. Calculate the difference of each of the other numbers and 5.
This is the result:

## 3 2 1 4 5 4 1 2 3

Does that make the symmetrical relationships clearer? How?

### Links to Sites with Information on China:

The Yellow River Culture - Richard Hooker
Yellow River - Li Guoying
Yellow River: Picture Gallery - Li Guoying

### Links to Sites with Information on Turtles:

Projeto Tamar
Sea Turtle Restoration Project
Sea Turtle Library

### Book by Clifford A. Pickover:

The Zen of Magic Squares, Circles, and Stars

### Other:

Correspondence with Philip I. S. Lei about Lo Shu
Book of Lo (Lo Shu) - hiakZ
Lo Shu Square - Wikipedia