dicksont

             Learning Target

        Add and subtract mixed numbers

                  Example

         Pretend you have a picture that you want to frame with the lengths of 9 4/6 Inches, & 5 4/5 inches. you would need to find the sum of the lengths.  So you do 9 2/3 *2=10 1/3, so two lenghts of the picture are 10 1/3.  Next you find the other two lengths. For that you do 5 4/5 * 2 = 11 3/5.  Then you add the four lengths together... Uh-Oh.  The lengths' fractions have different denominators.  Now you need to find the LCD (Least common denominator know as Liquid Crystal Display also).  Unless you don't realize, the LCD is 15.  You now change the denominators to 15, and divide the new denominator by the old denominator (don't change the new denominator) and multiply the numerator by the denominators divided by each other.  In this example you would do 15÷5=3.  So for the 11 3/5 fraction, you multiply 3*3=9.  Your new fraction is 11 9/15.  For the other fraction (10 1/3) you divde 15 ÷ 5 = 3.  Then, you multiply 1*3=3.  Your  new fraction is then 10 3/15.  Then you add them together.  11 9/15 + 10 3/15 = 21 12/15.  Now you know you need 21 12/15 Inches of frame.

         In short, you:

   #1 If you have a square or rectangle multiply the two sides you are given by two

   #2 Find the LCD

   #3 Divide the new denominators by the old denominators and multiply the numerator by the quotient

   #4 Add the numbers together

      Here is a liquid crystal display:

               Click here to read the lesson, and here to take a quiz.