Algebraic Expressions

Chapter 2

Algebraic Expressions

​Algebraic Expressions

How many magnets are there?

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​Section 1

Algebraic Expressions

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​2 x 3 + 2

Open Ended

Try using Keita's idea and find the number of magnets needed with 4 pictures. Please show your work.

Draw

Complete the table below

In the situation, the number of magnets needed changes as the number of pictures increases

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​1 Using letters to express quantity

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​2 x 3 + 2

If we see a pattern:

2 x (number of pictures) + 2 magnets

​Then, we can use a letter to express quantities

​1 Using letters to express quantity

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​2 x 3 + 2

Let "a " represent the number of pictures

So,

2 x (number of pictures) + 2 magnets

can be written as:

2 x a + 2

or

2a + 2

​1 Using letters to express quantity

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​2 x 3 + 2

Open Ended

Present in your own words: How many magnets will the students need to put up 28 pictures?

​Algebraic Expressions

​In Math, it is the use of letters to express quantities.

Some examples:

2 (a ) + 2 magnets

a x 5 + 40 grams

Open Ended

Write an expression to indicate the following quantities:

(1) The total weight of a case of b balls when the case weighs 1500g and each ball weighs 135g

Open Ended

Write an expression to indicate the following quantities:

(2) The change when 1000 yen is used to pay for six sheets of drawing paper when each sheet costs x yen

​Where:

a = number of notebooks, one notebook cost 120-yen

b = number of pens, one pen cost 100-yen

Total cost of a 120-yen notebooks and b 100-yen pens

120a + 100b = ? yen

Expressing quantities with two different letters

Open Ended

Write an expression to indicate the following quantities:

(1) The total amount of yen when there are x 10-yen coins and y 1-yen coins

Open Ended

Write an expression to indicate the following quantities:

(2) The number of people that can sit in a train car with a rows of 2 seats and b rows of 3 seats

​*number paired with a letter

​*any letter to express a quantity

​*addition (+) or subtraction (-)

​*number alone

Open Ended

Write an expression to indicate the following quantities:

(1) The amount of string remaining when c 5-cm pieces are cut from a string that is a cm long

Open Ended

Write an expression to indicate the following quantities:

(2) The area of a triangle with base of a cm and height of h cm

Poll

How do you feel about simplifying algebraic expressions?

• I feel pretty good!

• I think I understand most of it.

• I have some questions.

• I'm really struggling.

Multiple Choice

How many terms are in the following expression?

3x + y + 42

• 2 terms

• 3 terms

• 4 terms

Multiple Choice

How many terms are in the following expression?

5 - 72x + 43y - 109 + 5z

• 3 terms

• 4 terms

• 5 terms

• 6 terms

Multiple Choice

True or False: Fractions, like 5/8, are considered constants.

• True 

• False

Multiple Choice

True or False: Decimals, like 0.1, are considered constants.

• True 

• False

Multiple Choice

True or False: In the expression -4x + 2, the coefficient is 4.

• True

• False

Multiple Choice

What are the terms in the expression?
-4x + 6y - 2

• -4x, 6y, -2

• x, y

• 4x, 6y

• -2

Multiple Choice

What are the variables in the expression?
-4x + 6y - 2

• -4x, 6y, -2

• x, y

• 4x, 6y

• -2

Multiple Choice

What are the coefficients in the expression?
-4x + 6y - 2

• -4x, 6y, -2

• x, y

• 4x, 6y

• -4, 6

Multiple Choice

What are the constants in the expression?
-4x + 6y - 2

• -4x, 6y, -2

• x, y

• 4x, 6y

• -2

Multiple Choice

What are the terms in the expression?
4 + 16v

• 4, 16v

• 4

• v

• +16

Multiple Choice

What are the variables in the expression?
4 + 16v

• 4, 16v

• 4

• v

• +16

Multiple Choice

What are the coefficients in the expression?
4 + 16v

• 4, 16v

• 4

• 16

• +16

Multiple Choice

What are the constants in the expression?
4 + 16v

• 4, 16v

• 4

• 16

• +16

Multiple Choice

Which of the following expressions contains the coefficients 4 and -6?

• 4n - 6n + 4

• 4n + 6n - 4

• -4n - 6n

• -4n + 6n

Multiple Choice

Which of the following expressions contains the variables x, y, and z?

• 4x + 6y + 10z

• 4x + 6y

• 4x + 10z

• 6y +10z

Multiple Choice

What are the terms in the following expressions?
15n - 4

• 15n, -4

• 15n, 4

• 15, -4

• n

Multiple Choice

What are the variables in the following expressions?
15n - 4

• 15n, -4

• 15n, 4

• 15, -4

• n

Multiple Choice

Which answer choice is NOT an example of a constant?

• -5g

• 0.5

• 1.58

• -1/2

Multiple Choice

Which of the following answer choices is NOT an example of a variable?

• 8

• x

• u

• n