Objectives 1.2. To practice using variables to write expressions. To use expressions to solve problems. To develop and use formulas to find specific quantities. To identify restrictions on variables. To use a spreadsheet to make a chart. Review of Properties.
Commutative Property of Addition:
The order in which two or more numbers is added does not affect the sum: a + b = b + a
Commutative Property of Multiplication:
The order in which two or more numbers is multiplied does not affect the product: ab = ab
Associative Property of Addition:
How two or more addends are grouped does not affect the sum: (a + b) + c = a + (b + c)
Associative Property of Multiplication:
How two or more factors are grouped does not affect the product (a b) c = a (b c)
Identify and define the variable….
Robert received $60 for his birthday. Each week he spends $4 of the money to go to the batting cage.
a) Write an expression to show how much money, in dollars, Robert has left.
Let w = the number of weeks
b) Does any number make sense for the value of “w”?
If not, describe the values that do not make sense.
Anything greater than 15 weeks does not make sense
C + 10
Consider this expression, what does it mean?
Variables can represent many things…
Formulas are like algebraic “recipes” used to represent relationships between variables that describe situations in contexts.
For Example: the formula to convert degrees Celcius to degrees Fahrenheit is
Formulas and Spreadsheets
Perform the inquiry on pages 40-42.