Understanding Expressions

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# Understanding Expressions - PowerPoint PPT Presentation

Examples: 2 + 3 2 x 5. Teaching Concept #1. Understanding Expressions. An expression contains numbers and operations. Examples: 2 + 3 = 5 2 + 3 = 1 + 4 2 x 3 = 6. An equation has an equal sign to show that one expression is equal to another expression. Teaching Concept #2.

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## PowerPoint Slideshow about 'Understanding Expressions' - nura

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Presentation Transcript
Examples:

2 + 3

2 x 5

Teaching Concept #1

Understanding Expressions

An expression contains numbers and operations.

Examples:

2 + 3 = 5

2 + 3 = 1 + 4

2 x 3 = 6

An equation has an equal sign to show that one expression is equal to another expression.

Teaching Concept #2

Understanding Equations
Examples:

A drawing has pictures or symbols to match the numerals in the equation.

Teaching Concept #3

Drawing Pictures
Steve had six pieces of gum and then he bought two more.

How many pieces of gum does he have now?

Application #1

Example
Alice is arranging chairs in the gym. She set up the chairs in three rows of three chairs. How many chairs does she need?

Application #2

Example

Concrete Example #1

Example

The commutative property of addition and multiplication means that the numerals in the expression can be in either order and will be equal.

Concrete Example #2

Example

The zero property for addition means that zero added to any number will equal that number.

The property of one for multiplication means that one times any number will equal that number.

Step-by-Step #1

Demonstration

2 + 4 = 4 + 2

XXOOOO = OOOOXX

3 + 1 = 1 + 3

XXXO = OXXX

Step-by-Step #2

Demonstration

2 x 4 = 4 x 2

3 x 2 = 2 x 3

Step-by-Step #3

Demonstration

6 + 0 =

XXXXXX

4 + 0 =

XXXX

Step-by-Step #4

Demonstration

4 x 1 =

OOOO

3 x 1 =

OOO

Concrete Example

Examples

=

3 + 4 4 + 3

XXXOOOO OOOOXXX

2 x 3 3 x 2

=

4 + 0 4

XXXX XXXX

=

2 x 1 2

=