Doubles Unit of Study: Addition and Subtraction Strategies to 20 Global Concept Guide: 2 of 5

Content Development  “The use of doubles (double 6 is 12) and near doubles (13 is double 6 and 1 more) is generally considered a strategy for memorizing basic addition facts, There is no reason why children should not begin to develop these relationships long before they are concerned with memorizing basic facts.” Van De Walle, p. 139  It is important for students to be able to use a variety of strategies when adding and subtracting numbers within 20. Students should have ample experiences modeling these operations before working on fluency. A way to differentiate is by using smaller numbers.

Day 1  Day one will introduce students to doubles as a strategy to add.  Some students will have experience with the word “double,” but take time to have a class discussion of real world objects that come in doubles and the meaning of the term.  Create a real world doubles anchor chart. Include models and matching number sentences.  Modeling doubles with manipulatives (Cuisenaire rods, snap cubes, etc.) will build a foundation for doubles +/- one.

Day 2 and 3  Students will use their understanding of doubles to work through Day 2 and 3 where they will also incorporate doubles plus one and doubles minus one.  Use the problem solving model to open your lesson. Have students solve a word problem with a fact such as 6+7 and explain how they doubles facts from the previous lesson could help them solve this problems.  For a visual model, have students create both addends with snap cubes and line up side by side. Probe students about what they notice (that one addend is only one more than the other) and how doubles can be used to solve.

Day 3  By Day 3 students should be able to apply a doubling and explain how it works.  Click here for a video that shows a first grade student explaining how she uses these strategies. To increase the rigor of a task like this, incorporate a problem solving scenario.here

Enrich/Reteach/Intervention  Enrich  Doubles +1 Doubles -1 – Grab and Go Lesson 3.6 Doubles +1 Doubles -1  Go Math Going Deeper Chapter 3 p111  Go Math Chapter 3 p112, #13  Reteach  Mega Math – Counting Critters F and JFJ  Intervention/Small Group  Intensive Intervention TE K/1 – Skill 35

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