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Grade 8:  The Learning Equation Math

12.02 Adding and Subtracting Fractions (Like Denominators)

Number Operations

Refresher pp 14-15

Learning Outcomes:

The student will:

add_fract.gif (7290 bytes)

Adding Proper/Improper Fractions with Like Denominators

addend + addend = sum

1.  When the denominators are the same add the numerators together and place the sum over the like denominator.

2.  Reduce to lowest terms

subtract_fract.gif (7251 bytes)

Subtracting Proper/Improper Fractions with Like Denominators

minuend - subtrahend = difference

1.  When the denominators are the same subtract the subtrahend numerator from the minuend numerator and place the difference over the like denominator.

2.  Reduce to lowest terms

 

Select Add OPERATION. Read the message before you close the direction box. The focus for this activity are on fractions with like denominators. Create two fractions that have the same denominator. The output at the bottom of the screen will show the solution with fraction strips and "pencil and paper" method.

Link: LearnAlberta

Richard E. Rand's web site, Visual Fractions, is a fantastic site for fraction investigation.  The applets available on the site are very well designed and make fraction exploring fun.  Permission was given to display an earlier version of the applet:

Adding Fractions with Same Denominators Instructions - A variety of answers is accepted.

First Addend and Second Addend must be entered before the Explain button works.   If you need help writing proper fractions, check out:  Identify Fractions.

Summary for adding fractions with like(common) denominators:

  • Add the numerators and place the sum over the common denominator.

  • Reduce to lowest terms and/or change to a mixed number as necessary.

From Richard E. Rand's: VISUAL FRACTIONS

 

Subtracting Fractions with Unlike Denominators Instructions - A variety of answers is accepted.

Summary for subtracting fractions with like(common) denominators:

  • Subtract the second numerator from the first and place the difference over the common denominator.
  • Reduce to lowest terms and/or change to a mixed number as necessary.

Minuend and Subtrahend must be entered before the Explain button works.   If you need help writing proper fractions, check out:  Identify Fractions..

From Richard E. Rand's: VISUAL FRACTIONS

Proper and Improper Fraction Calculator

First Fraction

+

-

x

/

Second Fraction


Result

Source: Fraction Calculator v0.1
Review:

Integer Bars (Cusenaire Rods): Learning Fractions - pictorially

Pattern Blocks: Exploring Fractions with Shapes - pictorially

Adding and Subtracting Fractions

 

Enrichment:

Adding Fraction Slide Rule

 

Key Terms:

sum, numerator, denominator, proper fraction, improper fraction, mixed number, equivalent fractions, simplest terms, greatest common factor (GCF).

Pre- requisite Skills:

Converting Fractions:  Grade 7 Lesson 11.05

Converting Fractions:  Grade 7 Lesson 11.05

Converting Fractions:  Grade 7 Lesson 11.05

 

Converting Fractions:  Grade 7 Lesson 11.05

Lesson on Factors and Greatest Common Factors

Factor Tree

A diagram that shows the prime factorization of a number.

Change the value in the box and click the "Factor" button again to factor a new number.

source:  Factor Tree

 

Prime Factorization

A prime factorization of a number must be expressed as a product of prime numbers.  The prime factorization of 24 is 2 x 2 x 2 x 3 or 23 x 3, since:

2 x 2 x 2 x 3 = 23 x 3 = 24

Enter a number, then click to see the prime factorization of the number.

Formula to :

This formula may be an integer, a rational number, a polynomial or a rational function.

liniked source:  Factoris

 

 

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Comments to:  Jim Reed
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