Ms. Drake 7th grade Math

Number TheoryLesson 15

Variables and Algebraic Expressions

Week by Week Essentials Week 4

Number TheoryAddition Property of EqualityAlgebraic ExpressionBaseCoefficientComposite Number ConstantDivision Property of EqualityEquation

EvaluateExponentGreatest Common Factor (GFC)Inverse OperationsIsolate the VariableLeast Common Multiple (LCM)Like Terms

Number Theory

Number TheoryMultipleMultiplication Property of EqualityNumerical ExpressionOrder of OperationsPowerPrime FactorizationPrime NumberScientific NotationSolution

Number Theory

SolveStandard FormSubtraction Property Of EqualityTermVariableVerbal Expression

Algebraic Expression: an expression that contains

at least one variable.Example:

3 + x5(b-2)

Variables and Algebraic Expressions

Evaluate: to find the value of a numerical or algebraic

expression.

Variables and Algebraic Expressions

Constant: stays the sameA value that does not change.

2 always represents the value 2

5 always represents the value 5

Variables and Algebraic Expressions

What are examples of quantities that are

constant?

The year you were born…

The number of hours in a day…

Variables and Algebraic Expressions

Variable: varies- is not the same

A letter that takes the place of an unknown number or

numbers.

A symbol used to represent a quantity that can change.

What are some examples of quantities that vary?

The price of gasoline…

Temperatures….

Abdul entered a walk-a-thon for a local charity. His

sponsor provided the $20 entry fee and will provide $4

for each mile he walks.

How can we find out how much money Abdul could help

raise

Make a table to display the information

How would we write the expression if the number of miles walked is replaced by

the variable m?

Miles Walked Expression Amount 1 20 + 4(1) 24 5 20 + 4(5) 40

If Abdul walked 13 miles, how much would he earn for

charity?

What if Abdul wanted to earn $100 for charity? How many miles must he walk?

Evaluate each expressions for the given value of the

variable.

3x – 2 for x = 5

… for x = 7

28

Evaluate an algebraic expression with two

variables.

…Until next time solve this magic square with a partner.In a magic square each row,

column and diagonal will have the same sum.

Evaluate for x = 4 x = 6 and x = 0.

Which solutions are true?

This is a magic square only if after you solve each

expression, the sums of the solutions in each row, column and diagonal are the same.

7+4 11

4 4

2(4)+1 9

4+2 6

0.5(4)+6 8

4+6 10

3(4)-5 7

3(4) 12

4+1 5

24 24

24

24

24

24

24

24

6+6 12

6 6

2(6)+1 13

6+2 8

0.5(6)+6 9

6+6 12

3(6)-5 13

3(6) 18

6+1 7

33 32

38

33

29

31

35

28

Six is not a solution.

7+0 7

0 0

2(0)+1 1

0+2 6

0.5(0)+6 6

0+6 6

3(0)-5 -5

3(0) 0

0+1 1

8 8

-4

6

24

8

2

14

Zero is not a solution