1. Recognize Linear Relationships and Solve Equations with Technology Using an Excel Spreadsheet to Solve Equations iLearn Grade 7 Math Session 6 of 8

2. Focusing Questions How can a spreadsheet be used effectively to solve equations using guess-check-and-improve?

3. Instruction

4. Framing The Session “Guess-check-and-improve is an effective strategy to solve simple equations. It becomes more tedious to use this strategy as equations become more complicated. The process can become easier when a spreadsheet is used. We will learn to use a spread sheet to solve complex equations in an effective manner.”

5. Teaching You have learned in session 3 how to set up an Excel chart. Now we are going to set up a spreadsheet to solve the following equation: 3n + 5 = 5n + 3 2 3 “How can the spreadsheet be used to find the value of n?”

6. Guided Practice Guide participants through the process of setting up the spreadsheet: “Set up the spreadsheet, entering headings and formulas in the top two rows of the first four columns of the spreadsheet. “ ABCD 1Test Variable n Left Side =(3n+5)/2 Right Side =(5n+3)/3 Difference 2 0=(3*A2+5)/2=(5*A2+3)/3=B2-C2 3 1=(3*A3+5)/2=(5*A3+3)/3=B3-C3

7. Work Time

8. Getting Started Begin guessing by entering a value for n in cell A3. What happens when n = 0? When n = 1? Now we will manipulate a balance sketch in partnerships.

9. Work Time Work with a partner to solve for n. How do you know when you have found the solution? Examine your test variables. What strategies did you use to improve upon each guess?

10. Mid-workshop Teaching Now we will look at another equation: 4n + 1 = 3n + 8 2

11. Mid-Workshop Teaching Set up a new spreadsheet to test the equation.

12. Mid-Workshop Teaching Suppose I would like to test a range of values for n, such as 0 to 20. How can this be done without entering each value of n individually?

13. Mid-Workshop Teaching How can I represent consecutive numbers algebraically? Create a formula for cell A3.

14. Work Time Practice the “Fill Down” command to copy formulas. Copy the formula that is in cell B2. Paste it into rows 3 to 21. Continue to complete the spreadsheet and determine the value of n.

15. Share

16. What is the solution for the value of n? How do you know? Share

17. How can the use of a spreadsheet develop a better understanding of equation solving? What role does estimation play in equation solving? Share

18. How does this work address how a spreadsheet can be used effectively to solve equations using guess-check-and-improve? Answers

19. For more information Office of Instructional Technology oittc@schools.nyc.gov www.nyc.gov/schools