We put all of our fraction knowledge to work today. In order to add and subtract mixed numbers, we had to do all of the following:
- First, we had to convert our mixed numbers into improper fractions (p. 26 of our journal)
- Once we had our improper fractions, we needed to determine a common denominator (p. 25 of our journal). This includes:
- making factor trees for our two denominators
- creating a venn diagram to place our prime factors into
- determine our common denominator by multiplying all of the numbers on the venn
- Now that we have a common denominator, we have to make equivalent fractions with our improper fractions.
- Next, we add or subtract.
- Now take the answer, which is still an improper fraction, and turn it back into a mixed number (p. 26 our our journal)
- Now, we need to determine if it can be simplified (p. 25 of our journal). This includes:
- First, seeing if either the numerator or denominator is prime (p. 24 our our journal).
- If it is prime, then see if the other number is a multiple and divide by it.
- If it isn't prime then we need to find our greatest common factor.
- To find our greatest common factor:
- make factor trees for our numerator and denominator
- create a venn diagram to place our prime factors into
- any numbers in the center section of the venn need to be multiplied together, this is the GCF
- Once we have the GCF, the numerator AND denominator need to be divided by that number
We followed this procedure on our assignment, "A Magical Getaway." I found this worksheet in The Mailbox Magazine, Dec/Jan, 2011 issue, p. 12. To view the first four problems being solved, please watch: Adding and Subtracting Mixed Numbers.