Published on July 4, 2009
With Different Denominators
Adding Fractions Norm Frankenberger Summary Slide Why Adding Fractions Is Important? Identifying the Parts of a Fraction The Most Important Rule What If the Fractions You’re Adding Have Different Denominators Choosing a Common Denominator Converting Fractions to Equivalents Equivalent Fractions
Why Adding Fractions Is Important? In March 2008, a presidential panel reported after a two year study that “schools could improve students’ math scores by hammering home the basics, such as addition and multiplication, and then increasing the focus on fractions and geometry. In addition the report stated… Adding Fractions Norm Frankenberger
Adding Fractions Norm Frankenberger “Difficulty with fractions (including decimals and percents) is pervasive and is a major obstacle to further progress in mathematics, including algebra.” Success in algebra is linked to higher graduation rates and college enrollment. Let’s get started!
Norm Frankenberger Identifying the Parts of a Fraction The top number is called the numerator. The bottom number is called the denominator. 3 4 numerator denominator Adding Fractions
Norm Frankenberger The Most Important Rule You CANNOT add (or subtract) fractions unless the denominators are the same! 1 3 + 1 4 does not add up to 2 7 Adding Fractions
Adding Fractions Norm Frankenberger What If the Fractions You’re Adding Have Different Denominators You must choose a new common denominator You must change the fractions into their equivalent forms.
Adding Fractions Norm Frankenberger Choosing a Common Denominator 1 + 3 1 4 Go through the list of multiples of the two denominators and pick out the first number that appears in both lists. This is the common denominator!
Adding Fractions Norm Frankenberger Converting Fractions to Equivalents Put equal signs and the common denominator next to the original fractions Ask, “Three times what number equals twelve?” Answer: “Four” Now, whatever you do the bottom of the fraction, you must do to the top. Multiply the numerator times fourx 4 = 12 12 1 + 3 1 4 4 = = x 4 = x 3 = 3 x 3 = Now repeat the same process with the second fraction.
Put equal signs and the common denominator next to the original fractions
Ask, “Three times what number equals twelve?”
Now, whatever you do the bottom of the fraction, you must do to the top.
Multiply the numerator times four
Adding Fractions Norm Frankenberger Before we add the numerators… Let’s take a closer look at equivalent fractions: They are the mechanism by which we can change the original fractions into fractions with different denominators without losing the original value If it wasn’t for equivalent fractions we could not add (or subtract) fractions.
Norm Frankenberger Equivalent Fractions Equivalent fractions allow us to change a fraction to a fraction with a different denominator but with the same value. For example: == ½ ½ ½ In other words, ½ = 2/4= 4/8 2/4 4/8 Adding Fractions
Norm Frankenberger Now, Let’s Finish the Problem Now, you add the numerators and put the total over the common denominator. x 4 = 12 12 1 + 3 1 4 4 = = x 4 = x 3 = 3 x 3 = 7 12 Adding Fractions
Adding Fractions Norm Frankenberger I hope that helped and remember: "Numbers are your friends, especially when they are on your paycheck."
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Practice adding fractions. Math Computation Practice: Adding Fractions : More Pra ctic e : Fraction Activities
Equivalent Fractions. Some fractions may look different, ... Adding Fractions. It is easy to add fractions with the same denominator (same bottom number):
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So we're asked to add 3/15 plus 7/15, and then simplify; the answer. So just the process when you add fractions is if they; already-- well, first of all ...
A secondary school revision resource for GCSE Maths about foundation level fractions, addition, subtraction, multiplication and division
Math video teaches students how to add fractions with different denominators.
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Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, ... Example of adding fractions with unlike denominators;