Exploring Area, Polygons, and Geoboard Fractions
Transcription
Exploring Area, Polygons, and Geoboard Fractions
Exploring Area, Polygons, and Geoboard Fractions Objectives To guide children as they explore finding areas of o irregular shapes, make polygons with trapezoids, and form fractions on a geoboard. Explorations www.everydaymathonline.com ePresentations eToolkit Algorithms Practice EM Facts Workshop Game™ Family Letters Assessment Management Teaching the Lesson Key Concepts and Skills • Divide shapes to model fractions as equal parts of a region or collection. Common Core State Standards Interactive Teacher’s Lesson Guide Curriculum Focal Points Ongoing Learning & Practice 1 2 4 3 [Number and Numeration Goal 3] • Find area by counting square centimeters on grid paper. [Measurement and Reference Frames Goal 2] Playing Beat the Calculator Math Journal 2, p. 311 My Reference Book, pp. 124 and 125 1 calculator per child Ongoing Assessment: Recognizing Student Achievement • Model polygons using pattern blocks and geoboards. Use an Exit Slip (Math Masters, page 415). [Geometry Goal 2] [Operations and Computation Goal 1] Key Activities Exploration A: Children trace their hands and feet on centimeter grid paper and determine the area of their handprints and footprints. Math Boxes 10 7 Exploration B: Children build polygons and other shapes with trapezoids and use Pattern-Block Templates to record their work. Home Link 10 7 Math Journal 2, p. 252 Math Masters, p. 317 Exploration C: Children divide shapes made on a geoboard into fractional parts. Materials Home Link 106 Math Masters, p. 313 slate Exploration A: Per partnership: Math Journal 2, pp. 248 and 249 Math Masters, p. 314 Exploration B: Per group: Math Journal 2, p. 250 Math Masters, p. 315 trapezoid pattern blocks Pattern-Block Template triangle and rhombus pattern blocks (optional) Exploration C: Per partnership: Math Journal 2, p. 251 Math Masters, p. 316 geoboard rubber bands Differentiation Options READINESS Solving Equal-Parts Geoboard Problems Math Masters, p. 318 geoboard rubber bands ENRICHMENT Finding Fractional Parts Math Masters, p. 319 geoboard rubber bands Advance Preparation For the Math Message, make one copy of Math Masters, page 313 for every four children. Teacher’s Reference Manual, Grades 1– 3 pp. 61, 62, 134–138, 158, 159 758 Unit 10 Decimals and Place Value 758_EMCS_T_TLG2_G2_U10_L07_57685X.indd 758 3/3/11 10:32 AM Getting Started Mental Math and Reflexes Write sets of numbers on the board. Volunteers read the numbers aloud. Have children record the median of each set on their slates. Suggestions: Math Message Home Link 10 6 Follow-Up Count squares to find the area of each shaded figure. Ask children to share some of the making-change problems they made up and solved. 349, 487, 204, 981, 500, 487, 210 487 2,581; 2,005; 3,096; 8,888; 5,210 3,096 3,096 1. 7 square centimeters 7 sq cm 2. 1 Teaching the Lesson Math Message Follow-Up NOTE Point out that there are two other WHOLE-CLASS ACTIVITY ways to write square centimeter: sq cm and cm2. Do not expect children to use the cm2 notation, but be sure to expose them to it. (Math Masters, p. 313) Review answers. Ask children to explain how they determined the area for Problem 2. Some children may remember from Unit 9 that if more than _12 of a square centimeter is shaded, it is counted as 1 square centimeter; if less than _12 of a square centimeter is shaded, it is ignored. Children continue to use this rule in Exploration A. Teaching Master Name LESSON 10 7 Date Time Math Message Name: Name: Count squares to find the area of each shaded figure. Count squares to find the area of each shaded figure. 1. 1. 7 7 square centimeters Exploration A: Tracing Areas of Handprints and Footprints PARTNER ACTIVITY 2. PROBLEM PRO P RO R OBL BLE B L LE LEM EM SOLVING SO S OL O LV L VING VIN V IIN NG square centimeters 2. 7 7 sq cm sq cm (Math Journal 2, pp. 248 and 249; Math Masters, p. 314) Partners help each other carefully trace one hand and one foot (wearing a sock) on the centimeter grid pages. For the hand tracings, children should keep their fingers close together. They count all the whole square centimeters. If more than _12 of a square centimeter is inside a tracing, it is counted as 1 square centimeter; less than _12 of a square centimeter is ignored. Children trade papers and check each other’s counts. Name: Name: Count squares to find the area of each shaded figure. Count squares to find the area of each shaded figure. 1. 1. 7 7 square centimeters square centimeters 2. 2. 7 7 sq cm sq cm Math Masters, p. 313 293-347_EMCS_B_MM_G2_U10_576949.indd 313 3/1/11 4:29 PM Lesson 10 7 759-763_EMCS_T_TLG2_G2_U10_L07_57685X.indd 759 759 3/3/11 10:32 AM Teaching Master Name LESSON 10 7 Date As a follow-up, children can compare their actual hand and feet sizes to those of other class members. As they make these visual comparisons, ask them to predict which areas are about the same and which are larger or smaller. If there is time, children can try to predict areas of other small objects. Time My Handprint and Footprint Areas Work with a partner. 1. Trace your partner’s hand onto his or her journal page 248. When your hand is traced, keep your fingers close together. 2. Count the number of whole square centimeters inside your handprint. If more than half of a square centimeter is inside your handprint, count the whole square. If less than half of a square centimeter is inside your handprint, do not count the square. Adjusting the Activity Have children find the median values for all of the areas of the hands in the class. Repeat for all of the areas of the feet in the class. 3. Record the area of your handprint at the bottom of that page. 4. Trace your partner’s foot onto his or her journal page 249. (Keep your sock on your foot.) A U D I T O R Y K I N E S T H E T I C T A C T I L E V I S U A L 5. Count to find the area of your footprint. Record the area of your footprint at the bottom of that page. 6. Exchange journals and check each other’s counts. Count again if you don’t agree with your partner. Exploration B: Making Follow-Up Work in a small group. Compare your hand to other group members’ hands. Then compare your foot to others’. Predict the following: Whose hand areas are about the same? Whose are larger? Smaller? Whose foot areas are about the same? Larger? Smaller? SMALL-GROUP ACTIVITY Pattern-Block Worktables PROBLEM PRO P RO R OBL BLE B LE L LEM EM SOLVING SO S OL O LV LV VIN IIN NG (Math Journal 2, p. 250; Math Masters, p. 315) Compare your predictions to the areas you recorded. Math Masters, p. 314 293-347_EMCS_B_MM_G2_U10_576949.indd 314 3/1/11 4:29 PM Children pretend that the trapezoid pattern blocks are small worktables and that you, their teacher, want to make larger tables by fitting the small trapezoid tables together. Children first make some polygons and then try to make as many different-shape and different-size tables as possible. Student Page Date Children use trapezoids to build multiple shapes. Time LESSON 10 7 Using Pattern-Block Templates, children record their worktable shapes on journal page 250. Group members compare reports to try to find as many different worktable sizes and shapes as possible. The Area of My Footprint Adjusting the Activity ELL Have children use small triangle or rhombus pattern blocks to make more worktables. A U D I T O R Y K I N E S T H E T I C T A C T I L E Exploration C: Forming Fractions V I S U A L PARTNER ACTIVITY on the Geoboard The area of each is 1 square centimeter. Other ways to write square centimeter are sq cm and cm2. Answers vary. The area of my footprint is square centimeters, or sq cm. Math Journal 2, p. 249 229_262_EMCS_S_SMJ_G2_U10_57640X.indd 249 Children find their foot areas by counting whole square units. 760 3/3/11 7:38 AM (Math Journal 2, p. 251; Math Masters, p. 316) Partners take turns. After one partner forms a shape on the geoboard with one rubber band, the other partner tries to divide the shape into 2 (or 3 or more) equal parts using other rubber bands. Unit 10 Decimals and Place Value 759-763_EMCS_T_TLG2_G2_U10_L07_57685X.indd 760 3/3/11 10:32 AM Teaching Master Children record results on journal page 251. The geoboard dot paper on the journal page is for a 7 × 7 geoboard. If your children are working with a 5 × 5 geoboard, have them outline a 5 × 5 dot array. Name Date Time 10 7 Worktables LESSON Work in a group. Materials □ trapezoid pattern blocks □ Pattern-Block Template (1 per person) □ Math Journal 2, p. 250 Pretend that each red trapezoid pattern block is a small table. Your teacher wants to make larger worktables by fitting these small tables together. Try each of the following problems. Use a Pattern-Block Template to record the tables you make on journal page 250. 1. Make a worktable shaped like a hexagon. 2. Make a worktable shaped like a triangle. 3. Use more than 1 block to make a worktable shaped like a trapezoid. 4. Make a worktable shaped like a parallelogram. 5. Make another parallelogram worktable that has twice the area of the one you just made. 6. Make any other worktable shapes that you can with the trapezoids. Children divide shapes into fractional parts on the geoboards. Follow-Up Compare your reports. Find all the different-size and different-shape worktables that your group made. Adjusting the Activity ELL Math Masters, p. 315 Prepare several geoboard shapes ahead of time. Make most of the shapes so that they can be divided into equal parts, but include a few shapes that cannot be divided into equal parts. Have partners try to divide your shapes into equal parts before they make their own. A U D I T O R Y K I N E S T H E T I C T A C T I L E 293-347_EMCS_B_MM_G2_U10_576949.indd 315 3/1/11 4:29 PM V I S U A L 2 Ongoing Learning & Practice Playing Beat the Calculator PARTNER ACTIVITY Teaching Master (Math Journal 2, p. 311; My Reference Book, pp. 124 and 125) Name LESSON 10 7 See My Reference Book, pages 124 and 125 for directions. Children play Beat the Calculator to develop their recall of addition facts. Using the Fact Power Table on journal page 311, children should record facts for which they can beat the calculator by making a check mark in the box containing that fact. Whenever they receive three check marks next to a particular fact, they write the sum in that box to indicate that they know the fact from memory. The Caller should select problems at random from the Fact Power Table. Date Time Geoboard Fractions Materials □ geoboard □ rubber bands □ Math Journal 2, p. 251 Work with a partner. 1. One partner makes a shape on the geoboard with one rubber band. Example: 2. The other partner tries to divide the shape into equal parts using other rubber bands. The equal parts should be the same size and shape. 3. Take turns until each partner has made 3 shapes. 4. Record some of the shapes you divided on journal page 251. Show the equal parts. 5. Record some shapes on the journal page that you could not divide into equal parts. Ongoing Assessment: Recognizing Student Achievement Exit Slip Use an Exit Slip (Math Masters, page 415) to have children record the facts in boxes for which they have at least one check mark. Children are making adequate progress if they record all the facts from the Fact Power Table. Work in a group. 6. Check one another’s work. 7. Discuss these questions: Are shapes that can be divided equally special in some way? What about the shapes that cannot be divided equally? [Operations and Computation Goal 1] Math Masters, p. 316 293-347_EMCS_B_MM_G2_U10_576949.indd 316 3/1/11 4:29 PM Lesson 10 7 759-763_EMCS_T_TLG2_G2_U10_L07_57685X.indd 761 761 3/21/11 11:56 AM Student Page Date Math Boxes 10 7 Time LESSON INDEPENDENT ACTIVITY Math Boxes 10 7 (Math Journal 2, p. 252) 2. A pencil costs 95¢. An eraser 1. Draw at least one line of costs 35¢ more than the pencil. How much do the pencil and the eraser cost together? symmetry. Answer: Mixed Practice Math Boxes in this lesson are linked with Math Boxes in Lessons 10-9 and 10-11. The skill in Problem 6 previews Unit 11 content. $2.25 Sample answer 60 3. Write as dollars and cents. Eight in 4. dollars and forty-three cents: $8.43 $15.06 $50.17 5. Write <, >, or =. 1 hour > Home Link 10 7 (Math Masters, p. 317) Home Connection Children count squares to find the areas of figures. 101 102 15 marbles are shared equally. Each child gets 6 marbles. How many children are sharing? 30 minutes < 1 year = 1 week 2 children How many marbles are left over? 3 INDEPENDENT ACTIVITY 6. Use counters to solve. 3 months 7 days 97 Rule +9 98 89 Answers vary. fifty dollars and seventeen cents: 45 88 56 fifteen dollars and 6 cents: out 41 65 54 32 3 Differentiation Options marbles Math Journal 2, p. 252 229_262_EMCS_S_SMJ_G2_U10_57640X.indd 252 3/18/11 2:06 PM INDEPENDENT ACTIVITY READINESS Solving Equal-Parts 5–15 Min Geoboard Problems (Math Masters, p. 318) To explore dividing shapes into equal parts using a concrete model, have children solve the geoboard problems on Math Masters, page 318. Encourage children to share how they divided the shapes. Home Link Master Name Date Teaching Master Name Time 10 7 Family Note Date Time 10 7 Equal Parts Area HOME LINK LESSON In today’s lesson, your child found the area of shapes by counting square centimeters. As you observe your child finding the areas below, check that he or she is counting squares that are 1 1 more than _ shaded as 1 square centimeter and not counting squares that are less than _ 2 2 1 shaded. For Problem 4, see if your child has a suggestion for what to do if exactly _ of a 2 square is shaded. Remind your child that area is reported in square units. Other ways to write square centimeters are sq cm and cm2. 69 Please return this Home Link to school tomorrow. Count squares to find the area of each shaded figure. Use a geoboard to solve each problem. Record what you did below. 1. Make the square below on 2. Make the square below on your geoboard. Divide the square in half with a rubber band. Record what you did on the square below. your geoboard. Divide the square into 3 equal parts with rubber bands. Record what you did on the square below. Sample answer Sample answer 2. 1. 3. Make the square below 17 23 sq cm 3. on your geoboard. Divide the square into 4 equal parts with rubber bands. Record what you did on the square below. cm2 4. 4. Show four ways you can divide this rectangle into equal parts on a geoboard. Record your work below. Sample answers: Sample answer 11 9 square cm cm2 Practice 5. 56 + 29 85 6. 88 - 59 29 Math Masters, p. 317 293-347_EMCS_B_MM_G2_U10_576949.indd 317 762 Math Masters, p. 318 3/14/11 10:47 AM 293-347_EMCS_B_MM_G2_U10_576949.indd 318 3/1/11 4:29 PM Unit 10 Decimals and Place Value 759-763_EMCS_T_TLG2_G2_U10_L07_57685X.indd 762 3/21/11 11:56 AM Teaching Master ENRICHMENT Finding Fractional Parts INDEPENDENT ACTIVITY 5–15 Min (Math Masters, p. 319) To apply children’s understanding of fractions, have them draw the WHOLE when a fraction of the WHOLE is given. Children use a geoboard to complete Math Masters, page 319. Name LESSON 10 7 Date Fractional Parts Find the WHOLE for each fractional part shown. Record your work on the geoboards for each problem. 1. This shape is worth 1 _ of the whole shape. 2 Draw the rest of the shape. 1 _ 2. This shape is worth 3 of Planning Ahead For children’s Place-Value Books, you may want children to make sturdy back covers out of posterboard, cardboard, or file-folder stock. If so, you will need to prepare these covers before beginning the lesson. Each child will also need five paper clips to hold pages back when numbers are displayed. 1 2 Sample answer the whole shape. Draw the rest of the shape. If you want to use a demonstration Place-Value Book in Lesson 10-9, use Math Masters, pages 330–336. Staple the pages of your book together or, to allow for flipping of the pages, bind them with an inexpensive spiral binding. (Most quick-copy stores can provide this service.) You can also glue the digit pages to the pages of a spiral notebook. Time 1 3 Sample answer 1 _ 3. This shape is worth 4 of the whole shape. Draw the rest of the shape. 1 4 Sample answer Math Masters, p. 319 293-347_EMCS_B_MM_G2_U10_576949.indd 319 3/1/11 4:29 PM Lesson 10 7 759-763_EMCS_T_TLG2_G2_U10_L07_57685X.indd 763 763 3/3/11 10:32 AM