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Welcome to my math blog! The purpose of this blog is to help you stay informed about our learning and experiences that have taken place during our math class. I have also included links your child (and you) may want to use in order to supplement math learning in 5th grade.

Wednesday, January 21, 2015

Adding and Subtracting Fraction with Unlike Denominators



We worked with adding and subtracting fractions with unlike denominators.  The process can be daunting.  To see my classroom examples, please watch:  Adding and Subtracting Fractions with Unlike Denominators.

The process itself is:


  • Use the denominators of the two fractions you are working with the find the LCD using factor trees and Venn Diagrams.


  • Once you know the LCD, you now have to make equivalent fractions using your new LCD and the original fractions.
  • Next, you perform the given operation.
  • Now you have to determine if the answer is in simplest form.  

    • One way to do this is to look at the numerator.  If the numerator is a prime number, you need to see if the denominator is a multiple of that prime number.  If not, then you are done.  

  • To simplify the fraction, you need to make a factor tree for the numerator and the denominator.  Find any factors that the two numbers have in common and divide by that number.


This is not an easy process to remember, so we will continue working with finding LCD, making equivalent fractions, and simplifying with GCF.

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