7th Grade Math

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Expressions

PART A B C

Multi-Part

Lesson 1

D

GLE 0706.2.2

Understand and work with

the properties of and

operations on the system of

rational numbers. SPI 0706.3.1

Evaluate algebraic expressions

involving rational values for

coefficients and/or variables.

Lesson 1C Expressions 33

Algebraic Expressions

A pattern of squares is shown.

1. Draw the next three figures in the pattern.


2. Find the number of squares in each figure and record your data in a
   table like the one shown below. The first three are completed for you.
   Figure
   Number of Squares

1

3

2

4

3

5

456

3. Without drawing the figure, determine how many squares would
   be in the 10th figure. Check by making a drawing.


4. Find a relationship between the figure and its number of squares.

The number of squares in the figure is two more than the figure

number. You can use a variable to represent the number of squares.

A variable is a symbol that represents an unknown quantity.

number of squares

figure number

The branch of mathematics that involves expressions with variables is

called algebra. The expression n + 2 is called an algebraic expression

because it contains variables, numbers, and at least one operation.

Evaluate an Algebraic Expression

Evaluate n + 3 if n = 4.

n + 3 = 4 + 3 Replace n with 4.

= 7 Add 4 and 3.

Evaluate each expression if c = 8 and d = 5.

a. c - 3 b. 15 - c c. c + d

Main Idea

Evaluate simple

algebraic expressions.

Vocabulary

variable

algebra

algebraic expression

coefficient

define a variable

V

vv

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