Lesson 1

Order of Operations

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

TIMS Challenge

This item can be used as a Problem of the Week.

  1. This exercise builds students' understanding of the concept of average. Their answers will vary, but should average to 160. Note that the sum of the values should add up to 10 × 160 or 1600 inches. Have them switch papers with a partner and check. It will be interesting for students to see that different sets of numbers can yield the same average.
    Two possible sets of values for ten years:
    150", 170", 145", 175", 140", 180", 135", 185", 120", 200"
    and
    145", 150", 102", 146", 180", 218", 175", 154", 170", 160".
  2. Borneo is located in the tropics. Encourage students to research rainfall in various countries and states using a reference book or the internet.

D. The Rain in Borneo

The average rainfall in Borneo is 160 inches per year. The highest recorded annual rainfall was 225 inches and the lowest was 102 inches. (The wettest state in the mainland U.S. has an average rainfall of 56 inches.)

  1. Make up a possible 10-year record of the annual rainfall in Borneo so that the mean rainfall is 160 inches. Keep your values reasonable (102–225 inches). Explain how you worked on the problem and arrived at your answer. Use a separate sheet of paper.
  2. With such a high rainfall, where on Earth would you expect to find Borneo? Find Borneo on a map of the world.