The Addition/Subtraction Facts Table

Transcription

1 The Addition/Subtraction Facts Table Objectives To provide experience exploring patterns in sums of two dice; and to introduce the Addition/Subtraction Facts Table. epresentations etoolkit Algorithms Practice EM Facts Workshop Game Family Letters Assessment Management Common Core State Standards Curriculum Focal Points Interactive Teacher s Lesson Guide Teaching the Lesson Ongoing Learning & Practice Differentiation Options Key Concepts and Skills Compare sums of whole numbers. [Number and Numeration Goal 7] Find sums of whole numbers. [Operations and Computation Goal 1] Use the Addition/Subtraction Facts Table to find sums of 1-digit whole numbers. [Operations and Computation Goal 1] Identify and describe simple numerical patterns. [Patterns, Functions, and Algebra Goal 1] Key Activities Children generate addition facts by throwing a pair of dice. They record facts and observe patterns in the sums. Children learn to use the Addition/Subtraction Facts Table to find sums and to play Addition Top-It Playing the Difference Game per partnership: 4 each of number cards 1 (from the Everything Math Deck, if available), 40 tool-kit pennies Children practice subtraction skills with coins. Math Boxes Math Journal 2, p. 1 Children practice and maintain skills through Math Box problems. Home Link Math Masters, pp. 162 and 163 Children practice and maintain skills through Home Link activities. READINESS Charting Domino Sums per group: 2 sets of 6 6 dominoes Children chart the sums of dots on dominoes. ENRICHMENT Exploring Polyhedral Dice Rolls per partnership: 2 polyhedral dice, chart paper Children record sums and observe patterns when rolling pairs of 8-sided dice. Ongoing Assessment: Recognizing Student Achievement Use Mental Math and Reflexes. [Number and Numeration Goal 7] Key Vocabulary Addition/Subtraction Facts Table Materials Math Journal 2, p. 9 and inside front cover transparency of Math Masters, p. 324 (optional) per partnership: 2 dice, 4 each of number cards 0 9 (from the Everything Math Deck, if available) slate Advance Preparation Children will use the Addition/Subtraction Facts Table (Math Masters, page 324) often in this unit and for the rest of the school year. For Part 1, you may want to laminate the page and tape it to children s desks. For the optional Readiness activity in Part 3, divide a piece of chart paper into 11 columns (labeled 2 12). For the optional Enrichment activity in Part 3, divide a piece of chart paper into columns (labeled 2 16) for each partnership. Teacher s Reference Manual, Grades 1 3 pp Unit 6 Developing Fact Power

2 Getting Started Mental Math and Reflexes Have children estimate the cost of several items from the farmer s market. Mathematical Practices SMP2, SMP3, SMP4, SMP5, SMP6, SMP7, SMP8 Content Standards 1.OA.3, 1.OA.6 A small cucumber costs 20, and a large cucumber costs 40. About how much would a medium-sized cucumber cost? A small container of apple cider costs 80, and a large container of apple cider costs $1.00. About how much would a medium container of apple cider cost? A small bag of sunflower seeds costs $2.50, and a large bag of sunflower seeds costs $5.50. About how much would a medium bag of sunflower seeds cost? Math Message On your slate, write two addition facts that have 5 as a sum. Ongoing Assessment: Recognizing Student Achievement Mental Math and Reflexes Use Mental Math and Reflexes to assess children s ability to estimate. Children are making adequate progress if their answers for medium-sized items are somewhere between the costs for small- and large-sized items. [Number and Numeration Goal 7] 1 Teaching the Lesson Math Message Follow-Up WHOLE-CLASS Interactive whiteboard-ready epresentations are available at to help you teach the lesson. Children share addition facts. Write each sum-of-5 fact as a number model on the board until all of the facts and their turn-arounds are listed. Do not repeat a fact. Making a Dice-Throw Record of Facts (Math Journal 2, p. 9) SOLVING Partners take turns throwing a pair of dice. Both partners record each throw as an addition fact in the correct column of the table in their journals. The first time two numbers are rolled, they are recorded as a fact and as its turn-around fact. For example, for a throw of 4 and 2, and should be recorded above the 6. Ignore throws of 4 and 2 thereafter. Doubles facts are recorded only once. Date LESSON Unit Record each fact and its turn-around fact once. dice dots Order will vary. Student Page Dice-Throw Record Math Journal 2, p _EMCS_S_SMJ_G1_U06_ indd 9 3/21/11 11:28 AM Lesson 537

3 Student Page THIS BOOK IS PROPERTY OF: STATE PROVINCE COUNTY Book No. PARISH Enter information SCHOOL DISTRICT in space to the OTHER left as instructed PUPILS to whom this textbook is issued must not write on any page or mark any part of it in any way, consumable textbooks excepted. 1. Teachers should see that the pupil s name is clearly written in ink in every book issued. 2. The following terms should be used in recording the condition of the book: New; Good; Fair; Poor; Bad. ISSUED TO Year Used CONDITION ISSUED RETURNED, After children have filled in their tables, discuss the results. Ask questions such as the following: How many ways can you roll 2 (or 12)? There is one way to roll 2 (1 + 1) and one way to roll 12 (6 + 6). How many ways can you roll 9 (or 5)? 4 ways Why are there more facts in the 7 column than in any of the other columns? There are more different ways to throw 7 than any other number Adjusting the Activity EM3MJ2_G1_IFC_IBC.indd Math 2 Journal 2, inside front cover 2// 11:58 AM Ask children the following questions: For which sums are there an even number of facts? 3, 5, 7, 9, and 11 Why do odd sums have an even number of facts? Every fact has a turnaround fact. For which sums are there an odd number of facts? 2, 4, 6, 8,, and 12 Why do even sums have an odd number of facts? One of the facts for an even sum is a doubles fact. While every other fact has a turn-around fact, doubles facts do not. 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 Introducing the Addition/ Subtraction Facts Table (Math Journal 2, inside front cover) WHOLE-CLASS Give children a difficult fact to solve, such as They may use any method, including counting on a number line or number grid, using counters or tally marks, or counting on fingers. However, they may not use a calculator. Then have children share how they got their answers. You may wish to show children how to write their solution strategies. Direct children s attention to the Addition/Subtraction Facts Table on the inside front cover of the journal. Ask if anyone can tell how to use the table to find the sum of Distribute a sheet of paper to each child. Have children draw an arrow in the corner as shown in the margin. Then demonstrate how to find the sum of using the transparency of the facts table (Math Masters, page 324) and the paper with the arrow. 1. Find the 6 in the shaded column on the left side of the table. Move the arrow so it points to the Find the 8 in the shaded row at the top of the table. Move the paper horizontally across the page so that the right side of the paper is aligned with the 8 column. The arrow will point to, the sum of 6 and 8. (See margin.) 538 Unit 6 Developing Fact Power

4 Say several addition facts. Children use the paper and facts table to find the sums and then record the sums on their slates. Circulate and check that children are using their papers correctly. NOTE It is okay for children to look up either 6 and 8 or 8 and 6 on the Addition/Subtraction Facts Table. This is a good opportunity to discuss turn-around facts. Also, children can use the Addition/Subtraction Facts Table located on the inside front cover of their journals to find answers. Introducing Addition Top-It (Math Journal 2, inside front cover) Children play Addition Top-It to practice addition facts. The game is played with a deck of number cards, 4 cards for each number 0 9. (As many as 4 children can play, but at first, just 2 children should play.) Provide directions and then have children play at least one game. Children should play this game often in the next few weeks to practice the facts. Directions 1. Shuffle the deck and place it number-side down. 2. Each player turns over 2 cards and calls out the sum of the numbers. If the players don t know the sum, they may find it in the Addition/Subtraction Facts Table (Math Journal 2, inside front cover). Players should check each other s sums, using the table. 3. The player with the largest sum wins the round and takes all of the cards. 4. In case of a tie for the largest sum, each tied player turns over 2 more cards and calls out the sum of the numbers. The player with the largest sum takes all of the cards from both plays. 5. The game ends when not enough cards are left for each player to have another turn. 6. The player with the most cards wins. Variation: Have children practice finding sums of 3 addends using the Associative Property of Addition while playing Addition Top-It. Have children turn over 3 cards rather than 2 cards. As children play Addition Top-It, visit each partnership. Notice which facts children are solving and ask them to share their strategy for finding the sum. When necessary, direct children to the Fact Strategy Wall to assist them in finding a strategy. Playing Addition Top-It NOTE The facts table is one source for looking up facts. Do not expect all children to find the table easy to use at first. Encourage them to use the table so that they can eventually use it with ease. Lesson 539

5 Date LESSON Math Boxes 1. Write the sums. 7 + = 12 = = = Add = = = + 4 = Student Page Time 2. What is the missing rule? in in out Rule 4. Draw lines to match the shapes that look alike. Column A out Fill in the circle next to the best answer. A +3 B +2 C -2 D -5 Column B 2 Ongoing Learning & Practice Playing the Difference Game Children practice subtraction skills with coins by playing the Difference Game. For detailed instructions, see Lesson 5-7. Adjusting the Activity Have children record number models on half-sheets of paper for each round of play. For example, if Player 1 has 8 pennies and Player 2 has pennies, the number model is - 8 = 2. 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 Math Journal 2, p. 1 Math Boxes (Math Journal 2, p. 1) INDEPENDENT 9-136_EMCS_S_SMJ_G1_U06_ indd 1 NOTE Remember to use the Dice Roll Activity on a regular basis to practice fact strategies. See Lesson 5- for detailed instructions. When your class is ready, you may wish to try some of the variations listed in Lesson 5-. 2/3/11 9:36 AM Mixed Practice Math Boxes in this lesson are paired with Math Boxes in Lesson 6-3. The skills in Problem 4 preview Unit 7 content. Writing/Reasoning Have children draw, write, or verbalize an answer to the following question: How do turn-around facts help you learn math facts? A reasonable answer should explain that if you know one fact, then you also know its turn-around fact. One child s work in response to the Writing/Reasoning prompt 540 Unit 6 Developing Fact Power

6 Home Link (Math Masters, pp. 162 and 163) INDEPENDENT Home Connection Children find sums, using the Addition/Subtraction Facts Table and complete a color-bynumber picture. This Home Link consists of two pages. Name HOME LINK Home Link Master Finding Addition Sums Date Family Children continue practicing addition facts. Today they, Note learned how to use the facts table to find sums. Have your child explain how the table shows the fact =. Help your child find sums in the table. It is fine to solve the problems using other strategies, such as counting on or using counters to model the problems. Please return the second page of this Home Link to school tomorrow. Keep a copy of the facts table at home for future use. NOTE If you wish to have children practice sums to 20 using the Addition/Subtraction Facts Table, go to +, Differentiation Options READINESS Charting Domino Sums SMALL-GROUP 5 Min To provide experience charting sums using a concrete model, have children sort and chart domino sums. Children put each domino in the column labeled with the corresponding sum. (See Advance Preparation.) Encourage children to lay the dominoes in the columns horizontally and from the bottom of the column to the top. With a second set of 6 6 dominoes, children can add the turnaround facts to the chart. After the dominoes are sorted, discuss patterns on the chart. Sample answers: There are more dominoes in the middle columns. There is one domino in the 2 column and one domino in the 12 column. To support English language learners, review the meaning of the word sum. ELL Math Masters, p _EMCS_B_MM_G1_U06_ indd 162 py g g p 3/31/11 :22 AM ENRICHMENT Exploring Polyhedral Dice Rolls 30 Min To apply children s understanding of randomly generated dice sums, have them predict the results of rolling a pair of 8-sided dice. Discuss which of the true statements for the 6-sided dice roll might be true for the 8-sided dice roll. Then partners take turns rolling a pair of 8-sided dice and recording each roll as an addition fact and as its turn-around fact in the correct column on the chart. (See Advance Preparation.) Review the charted results to see if the predictions were accurate. To support English language learners, review the meaning of the word predict. ELL py g g p Name HOME LINK Date Finding Addition Sums continued Use the color code to color the picture. Color Code = = yellow 12 = blue = red Home Link Master = = yellow red blue = 12 blue blue yellow = red = Practice Show 37. Use Í, Â, and Î. Math Masters, p. 163 Sample answer: ÍÍÍÂÎÎ _EMCS_B_MM_G1_U06_ indd 163 2/2/11 :07 AM Lesson 541