`Adding Mixed Numbers with Unlike DenominatorsCamille Gales                  Edward Coles Elementary School                               8441 S. Yates Blvd.                               Chicago IL 60617                               (773) 535-6550Objective:This is a seventh grade activity designed to provide students with practice in adding mixed fractions with unlike denominators. Materials:tape measures; water soluble marking pens; 12 inch rulers; teacher made block letters of equal height but widths containing fractional parts including 1/16, 1/8, 1/4, 1/3, 1/2 (or any fractional part that can be measured by using a 12 inch ruler); long strips of fadeless paper or a roll of drywall tape; scissors; glue      Strategy:Review addition with mixed numbers, first at the board, then at the desk using individual worksheets.  When seatwork is complete pair the students.  Using a tape measure, each student will measure distance from his/her wrist to the tip of the longest finger.  Make a dot, with the marker, at that spot on the wrist where the measurement began.  Record the distance.  Next, measure the distance from the spot on the wrist to the inside fold in the arm where the forearm and upper arm meet.  Put a dot on that spot in the fold.  Record that distance.  Measure the distance from the inside fold in the arm to the shoulder joint.  Record it.  Sum the three measurements.  Measure the distance from the shoulder joint to the inside fold in the arm.  Compare the added length to the measured length. In the second activity students will select the precut letters to form such things as school name, first name or nickname.  Students will measure the width of each letter, allocate 1/4 of an inch space between each letter, and then add all letter widths and spaces.  Once the students have calculated the width of letters and spaces they will cut fadeless paper or drywall tape to equal the width of the calculated letters and spaces.  Paste the letters onto the fadeless paper or drywall tape. Performance Assessment:In the first activity, if the students have measured and added correctly, the sum of the three measurements should equal the distance measured from shoulder joint to finger tip.  In the second activity, the length of the fadeless paper or drywall tape should be equal to the sum of the letters and spaces.  Both activities are self checking.Grading Rubric    If the error in measurement is within 1/4 of an inch a grade of A should be awarded.  If the error in measurement is within 1/2 of an inch a grade of B should be awarded.  If the error in measurement is within 1 inch a grade of C should be awarded.  If the error in measurement is within 1 1/2 of an inch a grade of D should be awarded.  If the error in measurement is greater the activity should be redone. Conclusions:This activity enables the student to put math concepts to practical use.  It also motivates the student to measure correctly.  Finally, the self-checking mechanism makes the activities easy to grade.  `