Addition Strategies That Use Doubles Facts

Transcription

1 Addition Strategies That Use Doubles Facts Objective To provide opportunities for children to explore and practice doubles-plus- and doubles-plus- facts. 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 Practice doubles facts. [Operations and Computation Goal ] Develop and practice strategies for addition that use doubles facts. [Operations and Computation Goal ] Use doubles patterns to practice facts. [Patterns, Functions, and Algebra Goal ] Key Activities Children identify and practice strategies for facts in which one addend is or more than the other addend. Ongoing Assessment: Recognizing Student Achievement Use the Math Message. [Operations and Computation Goal ] Key Vocabulary doubles-plus- facts doubles-plus- facts Playing Domino Top-It per partnership: set of dominoes Partners practice addition facts. Cutting Out Fact Triangles Math Journal, Activity Sheets and scissors envelope per child Children cut out the first set of Fact Triangles. Math Boxes Math Journal, p. Children practice and maintain skills through Math Box problems. Home Link Math Masters, p. Children practice and maintain skills through Home Link activities. READINESS Designing a Doubles Facts Book pattern blocks Pattern-Block Template paper and pencil Children explore doubles facts using a concrete model and create a Doubles Facts Book. ENRICHMENT Exploring Calculator Doubles Math Masters, p. calculator Children use calculators to explore the concept of doubles addition facts. Materials Math Journal, pp. and Home Link slate paper Advance Preparation Before the lesson, draw a unit box on the board and fill it in with a label of your choice. Use the unit box and label for all the numbers that are not labeled in this lesson. Teacher s Reference Manual, Grades pp. Unit Addition and Subtraction Facts

2 Getting Started Mental Math and Reflexes Pose + facts. Encourage children to think +, then count back. Suggestions: + =? + =? + =? + =?? = +? = + +? = +? =? + = Math Message Write all the doubles addition facts on a sheet of paper. Home Link Follow-Up Review answers as necessary. Teaching the Lesson Math Message Follow-Up (Math Journal, p. ) NOTE Remember to reserve time every day to complete the number-line, attendance, calendar, temperature, and weather daily routines. See Daily Routines on page xxxv of this book and Teacher s Reference Manual, pages. Ongoing Assessment: Recognizing Student Achievement Math Message Use the Math Message to assess children s knowledge of doubles facts. Children are making adequate progress if they can correctly record all of the doubles facts. [Operations and Computation Goal ] Ask children to turn to the Facts Table on journal page. Help them as needed while they check their list of doubles facts against the table. Remind children that sums of all doubles facts are even. Discussing Doubles-Plus- Facts Doubles-plus- facts include those addition facts in which one addend is more than the other addend (for example, + ). Write some doubles-plus- facts on the board; leave out the sums. Use both horizontal and vertical forms. (See page.) Ask children to copy and complete the facts on their slates. See whether any children mention a strategy that makes use of doubles. Discuss the doubles-plus- strategy. To add numbers where one addend is more than the other, double the smaller number and then add. NOTE Knowledge of doubles facts is important as this lesson focuses on strategies that assume quick recall of these facts. Daily chanting of the doubles will help reinforce this skill. Addition/Subtraction Facts Table Math Journal, p. Lesson

3 + = = + + = = Discussing Doubles-Plus- Facts Doubles-plus- facts are addition facts in which one addend is more than the other addend (for example, + ). Write some doubles-plus- facts on the board; leave out the sums. Use both horizontal and vertical forms. (See margin.) Ask children to copy and complete the facts on their slates. See whether any children mention a strategy that makes use of doubles. Discuss doubles-plus- strategies. To add numbers where one addend is more than the other addend, double the smaller number and add. Some children may discover that they can change a doubles-plus- fact into a doubles fact by subtracting from the larger addend and adding to the smaller addend, for example, they might change + into the doubles fact +. Practicing Addition Strategies That Use Doubles Facts (Math Journal, p. ) PROBLEM SOLVING Children practice and extend the doubles-plus- and doubles-plus- strategies and extend them to doubles-plus- facts. Addition Facts Ongoing Learning & Practice Playing Domino Top-It PARTNER If you know a double, you know the -more and the -less sums. Example: If you know that, You know, And Have partners place dominoes face down between them. Each player turns over a domino and calls out the sum of the dots on the two halves. The player with the higher sum wins and takes all the dominoes currently in play. Domino Top-It is suggested in anticipation of Lesson -, in which children use dominoes to construct subtraction facts. Try This.... Math Journal, p. Unit Addition and Subtraction Facts

4 Cutting Out Fact Triangles (Math Journal, Activity Sheets and ) Have children cut out the Fact Triangles from Activity Sheets and. You might want to have them write their initials or draw a distinctive pattern on the back of each triangle. This will help children identify their individual sets. Tell children to store the Fact Triangles in envelopes in their tool kits when they are not using them. These Fact Triangles will be used in Lessons - and - through - as addition and subtraction flashcards. In Lesson -, children will cut out a second set of Fact Triangles from Activity Sheets and. Math Boxes (Math Journal, p. ) Mixed Practice Math Boxes in this lesson are paired with Math Boxes in Lesson -. The skills in Problems and preview Unit content., Fact Triangles Math Journal, Activity Sheet Home Link (Math Masters, p. ) Home Connection Children complete a page of addition facts and draw a path from the child to the ice-cream cone by connecting sums of,, or. Math Boxes Home Link Master Name HOME LINK Addition Facts Maze. What shape is the cover of your math journal? Fill in the circle next to the best answer. A B C D. Complete the fact family. Fill in the missing domino dots.. Put the numbers in order from smallest to largest. Circle the middle number.,,,, rhombus rectangle triangle square,,,, Math Journal, p.. Circle the activity that takes about second. Blinking your eyes. Writing your name. Reading a story.. How likely is it that our school will have a fire drill today? Circle your answer. certain likely unlikely impossible Answers vary.. Draw hands to show :. Family Note For homework, your child will review addition facts like the ones we have been working on in class. To help identify the path from the child to the ice-cream cone, have your child circle the sums of,, and. Please return this Home Link to school tomorrow. Help the child find the ice-cream cone. Answer all the problems. Then draw the child s path by connecting facts with sums of,, or. You can move up, down, left, or right as you move between boxes. Math Masters, p. Lesson

5 Name You can program the calculator to solve doubles problems.. First clear your calculator.. Enter,,,. (The calculator will display a ). Do NOT clear your calculator again while you work on this page.. Guess what the sum is for double ( + ).. Now enter and press. What does the calculator display?. Guess what the sum is for double ( + ).. Now enter and press. What does the calculator display?. Make up your own doubles problems for the calculator to solve. Record your number sentence and the sum the calculator displays. Example: Sample answers: Try This Calculator Doubles. Why do you think you entered on the calculator to program it to solve doubles problems? Sample answer: I think each X shows more times. So you keep adding the given number that many times. Math Masters, p. Teaching Master Differentiation Options READINESS Designing a Doubles Facts Book Min To explore doubles facts using a concrete model, have children design a Doubles Facts Book using their Pattern-Block Template. First, have children create a doubles fact using pattern blocks of the same shape. Next, children copy the design onto a sheet of paper using their template. Each design shows a doubles fact accompanied by a number model. Staple the pages together to create a Doubles Facts Book. In addition to having children describe their double designs using color and shape words, have them identify the sum as odd or even. For example, There are three sides on each green triangle. I have two green triangles. Three plus three equals six. There are six sides in my design. Six is an even number. There are two red trapezoids and two yellow hexagons. Two plus two equals four. There are four shapes in my design. Four is an even number. Ask children what they notice about the sums of the doubles facts. Sample answer: They are even. Have a volunteer explain why the sums of doubles facts are even. Sample answer: When even numbers or odd numbers are added together, the sum is always even because you will always have pairs. ENRICHMENT Exploring Calculator Doubles (Math Masters, p. ) PARTNER Min To further explore the concept of doubles addition facts, have children work with a partner to solve doubles problems on a calculator. Unit Addition and Subtraction Facts