Writing and Interpreting Expressions

Write and Identify Expressions

By Kevvin Hankins

Standard

Write, read, and evaluate expressions in which letters stand for numbers.

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​Learning Targets

• Write expressions with unknowns.

• Identify mathematical terms and use them to write or interpret expressions.

• Evaluate expressions with unknowns using the order of operations.

• Recognize and use expressions as common real-world formulas (i.e. volume of a cube, V = s³).

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Algebraic Expressions

What is an Algebraic Expression?

An algebraic expression in mathematics is an expression that is made up of variables and constants, along with algebraic operations (addition, subtraction, etc.). Expressions are made up of terms. 

Variables, Coefficients, Constants & Terms

• In the expression pictured,

  x is a variable, whose value is unknown to us which can take any value.

• 5 is known as the coefficient of x, as it is a constant value used with the variable term and is well defined.

• 3 is the constant value term which has a definite value

• The whole expression has two terms. Terms are separated by addition and subtraction signs.

Multiple Choice

Identify the constant in the expression.

2y + x + 8 + 7p

• 7

• 2

• 1

• 8

Multiple Choice

Identify the coefficient in the expression.

6y + 7

• 6y

• 7

• 6

• 1

Multiple Choice

Identify the Variable in the expression 5y+7?

• x

• 5y

• y

• 7

Multiple Choice

How many terms are in the algebraic expression?

2y + x + 4 + y²

• 4

• 3

• 5

• 2

Order of Operations

Mathematicians have devised a standard order of operations for calculations involving more than one arithmetic operation.

Multiple Choice

Which operation is performed FIRST?
(13 - 1) + 4

• addition
• subtraction
• multiplication

Multiple Choice

Which operation would you do first?

( 12 + 10) ÷ 10 · 14 - 6

• Division

• Multiplication

• Addition

• Subtraction

Multiple Choice

Which operation should be done first? $$3\ \times\ 4\ +\ 8\ -\ 2$$  

• addition

• subtraction

• multiplication

• division

Multiple Choice

Which operation is performed FIRST?

44 ÷ 2 X 3 -1

• muliplication X

• division ÷

• subtraction -

Multiple Choice

Solve :

18 - (9 - 2) =

• 7

• 11

• 5

Multiple Choice

11² - 8 ⋅ 7 + 2

• 100

• 793

• 67

• 49

How to Evaluate an Algebraic Expression

To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations.

Multiple Choice

Evaluate when a = 15:

2(a - 5) + 2

• 22

• 27

• 14

• 7

Multiple Choice

2x + 3 + x²; for x = 4

• 17

• 27

• 19

• 25

How to Write an Algebraic Expression

Generally, you'll do this by replacing the words with operators that mean the same thing.

Multiple Choice

Choose the algebraic expression that matches the verbal phrase.

Multiple Select

Choose the algebraic expression that matches the verbal phrase. Choose all that apply.

Multiple Choice

Choose the algebraic expression that matches the verbal phrase.

Multiple Select

Choose the algebraic expression that matches the verbal phrase. Choose all that apply.

Multiple Select

Choose the algebraic expression that matches the verbal phrase. Choose all that apply.

Thank You, Gracias, Danke, Merci, Spasibo

for learning with me today!