1. Date: 25-08-14
OBJECTIVE: Find equivalent algebraic expressions by using a spreadsheet tool
ALGEBRAIC EXPRESSIONS AND SPREADSHEETS
Read the information and follow the instructions. Solve questions 1 to 7
1. OPEN EXCEL PROGRAM
A spreadsheet is a software program that organizes data and performs calculations. Algebraic expressions or formulas are used to give the computer instructions for carrying out the calculations.
A spreadsheet is a table with columns and rows. Usually the rows are named with numbers and the columns are named with letters. The intersection of a row and a column is called a cell.
The display below shows the columns from A to H, the rows from 1 to 10, and the cell C6 has been shaded. Cell C6 means the cell in column C and row 6.
Many kind of information can be put in a cell: word, numbers, or formulas. Use double click to put information in a cell. Move through the cells with the arrows.
Evaluating algebraic expressions by using a spreadsheet.
To evaluate an algebraic expression with a spreadsheet, the formula associated with the given expression can be used. In this activity three different algebraic expressions that involve variables labeled as a, b, and c, will be evaluated.
2. Algebraic expression: a+b-c
Follow the steps.
(i) Enter the information given in the following table. The table shows five different values for variables a, b, and c. Start in cell A1
a
b
c
-3
7
-8
2
-4
-9
6
-5
2
-4
2
-9
3
-1
-7
2. (ii)Fill cell D1 with the algebraic expression: a+b-c. (iii)Go to cell D2. Double-click the cell and use = sign to enter the formula. According to the algebraic expression a+b-c, the suitable formula would be : = A2+B2-C2, because the numbers -3, 7, and -8 used to evaluate the expression are in cells A2, B2, and C2, respectively.
Type this formula in cell D2 followed by enter. The number 12 found, corresponds to the value of the expression a + b-c when a=-3, b=7, and c=-8. Notice that, while the cursor is over cell D2, the corresponding formula is showed on the formula bar.
(iv) To evaluate the expression for all the values in columns A, B, and C:
Click the cell D2
Copy the formula (ctrl-C or “copiar”)
Drag the cursor down to shade column D
Paste the information (crtl-V or “pegar”), and finally click enter key.
3. The column D will show the value of the algebraic expression a+b-c for the corresponding values of a, b, and c.
3. Algebraic expression: a(b+c)
Follow the steps
(i)Fill cell E1 with the algebraic expression: a(b+c). (ii) Go to cell E2. Double-click the cell and use = sign to enter the formula. According to the algebraic expression a(b+c), the suitable formula would be : = A2*(B2+C2). The sign * is used to indicate multiplication.
Edit this formula in cell E2 followed by enter. Look at the formula bar to check the formula.
(iii) To evaluate the expression for all the values in columns A, B, and C:
Click cell E2
Copy the formula (ctrl-C or “copiar”)
Drag the cursor down to shade column E
Paste the information (crtl-V or “pegar”), and finally type enter.
4. 4. Repeat the process to evaluate the algebraic expression: ab + ac
Equivalent expressions.
Two algebraic expressions are equivalent if they have the same value when each one is evaluated for any set of given values. Comparing the values in the spreadsheet columns can be used to determine whether two algebraic expressions are or not equivalent.
5. Compare the values in the spreadsheet columns and type the equivalent expressions that have been found, in cell D10
6. Additional Practice. Create two equivalent algebraic expressions. Use columns G and H to prove whether the expressions are equivalent.
7. SAVE YOUR WORK
