Sums and Differences Via Pattern Blocks

Needed for this lessonAt least three sheets of the triangle graph

paper available at http://math.rice.edu/~lanius/images/triangle.gif

Part 1•To complete the questions from Part 1,

▫You can use the triangle paper printed from the link on the prior slide

▫You can use the applet from the website: http://ejad.best.vwh.net/java/patterns/patterns_j.shtml

•Solutions are on the next slide for Part 1.

Sums and Differences Via Pattern BlocksPart 1. Answer the following questions. For Questions 1 – 4, write and

solve the arithmetic problem described.  If the yellow hexagon = 1, then the red trapezoid = _______, the blue

rhombus = ________, and the green triangle = _______. 1. Adding 1 green triangle and 2 green triangles illustrates what

arithmetic problem? 2. Adding 1 blue rhombus and 1 blue rhombus illustrates what

arithmetic problem? 3. Adding 1 red trapezoid and 1 red trapezoid illustrates what

arithmetic problem? 4. Adding 3 green triangles and 2 green triangles illustrates what

arithmetic problem?

1/2

1/6 + 2/6 = 3/6 = 1/2

1/61/3

1/3 + 1/3 = 2/3

½ + ½ = 2/2 = 1

3/6 + 2/6 = 5/6

Problems from Part 2 of the handout•For each problem illustrate the process of

addition or subtraction with the manipulatives on separate sheets of paper (triangle paper). Record the mathematics symbolically beneath each step in the process of addition or subtraction.

Video: Adding Fractions•Video 1st part of sums and differences

(addition)

•After watching the video complete # 3, check your solution process on the next slide

Solution to number 3

Be sure to show the equivalent fractions as that is key to moving to solving problems with the algorithm

Video: Subtracting Fractions•Video 2nd part of sums and differences

(subtraction)

•After watching the video complete # 6, check your solution process on the next slide

For subtraction problems, be sure to show the “take away” process on the first fraction

Solution to number 6

Video: Changing the Whole•Video 3rd part of sums and differences (whole

changes to 4 hexagons

•After watching the video complete #’s 9 - 12, check your solution process on the next slides

Solution to 9 and 10

Solution to 11 and 12