Using one centimeter to represent the actual five centimeters to draw the cover of the math textbook is to shrink the math textbook five times according to the ratio of 1: 5.

1, the ruler measures the actual length and width of the cover of a math textbook.

2. Multiply the length and width by one fifth respectively to get the result.

3. Using the obtained results, we can draw a graph with the textbook cover reduced by five times.