Hints There are two versions available for the Sears Tower activity:

Activity Instructions (Version 2a  Logical Analysis) 1. Distribute copies of Version 2 of the Sears Tower activity to all students. 2. Have students work independently for 30 minutes filling in the blanks with the numbers. Invite students to skip around and fill in numbers they are more sure about and later return to blanks they are less sure about. 3. Describe how some numbers are very unique; these numbers can be filled in and quickly eliminated from the possible list of numbers. Explain that some statements represent equivalencies and they should look for two numbers that meet the equivalency statement. Suggest to the students that they may want to expand the numbers that are represented with scientific notation. 4. Group students in groups of three to compare and discuss their answers. Ask them to verify their answers by showing equivalency statements, where appropriate. 5. When most groups have finished, ask some groups to report their results and procedures for verifying their answers. 

Reminder! This version increases the difficulty of the activity and more time needs to be allotted if using this version. Tip: Students with a good basic understanding of number sense will enjoy and be challenged by this version greatly. 
Activity Instructions (Version 2b  Web Scavenger Hunt) 1. Group students (preferably in pairs) and prepare for working on computers with Internet Web access. 2. Distribute copies of Version 2 of the Sears Tower activity to each pair. 3. Instruct the students to use the Related Web Sites to find the numerical facts represented in each of the statements, and then fill in the blanks with the appropriate numbers listed in the column on the right. 4. Ask students to verify their answers by showing equivalency statements, where appropriate. 5. When most groups have finished, ask some groups to report their results.
