S. B. Kizlik, Ed. D.

     LESSON  PLAN  FOR  GRADE  4, 5, 6
(Subtraction of Mixed Numbers)

            format example

 I.            Content

     Academic rule for subtracting mixed numbers with regrouping or trading
     Students have already learned to subtract mixed numbers without trading
     or regrouping.  

II.            Instructional Objectives

      The students will subtract 2 mixed numbers requiring regrouping or
       trading with a difference less than 50.             

III.        Instructional Procedures

A.  Beginning Review

-Get the attention of students; remind them of proper procedure behaviors.
-Direct students to get out their math notebooks and pencils
-Put students with their partners (groups of 2)
-Review the topic of subtracting mixed numbers that do not require regrouping
-Question
            “What is a mixed number?”  (Whole number plus a proper fraction)
-Call one student to the overhead to display the value of 3 2/5 using Cuisenaire
  rods.  Call another student to display the value of 2 5/8.
-Discuss the results and any questions
-Distribute fraction strips to the groups
-Direct students
  “Work with your partner and display the values for these mixed numbers.
  Leave your displays on the desktops so I can check them as I come
  around to help.
                        4 2/5               2 ¾                 6 5/8
-Circulate, assist, and check solutions
-Discuss results and questions
-Pose the question
 “What if we had 7 ¾ pizzas and gave 4 ¼ to Mr. Jackson’s class?  How  much pizza would we have left?”
-Discuss the information, the question, a plan for solving
-Call one student to the overhead to display the process using the rods
-Call another student to the board to demonstrate the process in written form:
            7 ¾  -  4 ¼ = 3 2/4  = 3 ½
-Stress that answers should always be written in lowest terms
-Direct students
            “Do the following problems in your math notebooks.  Show your work.
                        5 2/3  -  1 1/3              8 4/5  -  3 2/5

-Circulate, assist, and check accuracy
-Discuss results and questions.

B.  Presentation

-Begin subtraction with regrouping or trading through examples
-Have students consider
                    5 2/5  -  2 3/5
-Question
          “Look at the fraction values in the mixed numbers.  Are there enough fifths in 2/5 to remove 3/5 of them?” (call on a student to answer.)
-Direct class to work with their partners, use their fraction strips, and consider
  the answer to this question for a minute or so
          “How can we make enough fifths from  5 2/5 to be able to  remove 3/5 of  them?”
-Circulate, assist
-Have a group demonstrate, using fraction strips on the overhead, trading a
 ONE from the whole number, trading it for the equivalent fraction pieces in
 fifths, and combining it with the 2 fifth pieces that are already there, showing
 4 wholes and 7 fifths.
-Discuss trading a ONE for its fraction value
                 trade a ONE from the whole number 5, making the one 5/5 and
                 leaving the whole number 4 in place of the 5, combining the fraction
                 5/5 with the fraction 2/5 leaves the mixed number 4 7/5.
-Demonstrate this trading process in written form
          5  2/5 = 4 + 5/5 + 2/5 = 4 7/5
-Demonstrate how it affects the subtraction (fraction – fraction and
  whole – whole) using both fraction strips and written form
                              5 2/5 = 4 + 5/5 + 2/5 = 4 7/5
                            - 2 3/5=                        = 2 3/5
                                                                    2 4/5
-Direct the groups to use their fraction strips and written form to solve these
 problems
          6 1/3  -  3 2/3           3 3/5  - 1 4/5
-Circulate, assist
-Have a group demonstrate, using fraction strips, the first problem on the
 overhead
-Discuss the process
-Demonstrate the written form on the board
-Stress that the ONE changes to a fraction with numerator and denominator
  the same, and that is the same as the denominator of the fraction in the
  mixed number
-Stress the importance of writing the answers in simplest terms.
-Have a student demonstrate the written form of the second problem
-Discuss the process
-Leave the problems on the board for the students to reference
-Direct the students to work these problems in their notebooks
                    7 3/8  - 3 7/8              12 4/7  - 8 6/7           9 5/6  - 2 1/6
-Circulate, assist, check accuracy
-Have a student work each problem on the board
-Discuss any questions
-Note that the last problem did not require trading a one from the whole number
 because there were enough sixths to remove already

 C.   Ending Review

-Stress when you need to trade a one from the whole number and when
  it is not necessary by pointing to the last group of practice problems.
-Stress that the one must be written using the same denominator so it can
  be combined with the fraction that is already present in the minuend.
-Direct students to begin their assignment
-Circulate and assist

IV.       Materials and Equipment

1.            fraction strips for the class and the overhead

2.            Cuisenaire rods for the overhead

 V.        Assessment / Evaluation

           Student achievement during the class will be measured informally through
           teacher observation because this is the very first lesson on subtracting mixed
           numbers with regrouping or trading.  Student achievement will also be
           measured on the assignment.

VI.       Follow-up Activities

            -Students will be given page 45 for their assignment.
-Tomorrow the process will be reviewed and applied to word problems.

 VII.    Self-Assessment

           -Were the students able to follow my directions with little or no confusion?
           -Were the processes, situations, and rules concise, precise, and age-level
            appropriate?
           -Did the class achieve at least 88% success on the practice problems?
           -What did I do very well?
           -What could I have done better?
           -How will I do this better next time?