Presentation on theme: "Using Place Value to Add"— Presentation transcript:

Unit of Study: Two Digit Addition and Subtraction Global Concept Guide: 3 of 3

Content Development In this GCG, students will be using place value concepts to solve two digit number addition problems. In first grade, students will regroup ones into tens on a place value chart but they will not learn the standard algorithm for regrouping. “The word regroup may have little meaning for young children. A preferable term to use initially is trade. Ten ones are traded for a ten.” Van de Walle, Elementary and Middle School Mathematics: Teaching Developmentally, page 223 Students will build this understanding of tens and ones with manipulatives (base 10 blocks) and transition into quick pics. Students will use these strategies to add and subtract within 100. By the end of this GCG, students are expected to use quick pics for base ten models.

Day 1 3 tens + 0 ones 2 tens + 5 ones 5 tens + 5 ones 50 + 5 = 55
Essential Question: How can you model tens and ones to add two digit numbers? Engage: Go Math Lesson 8.7, Listen and Draw p Students will use base ten blocks on the place value chart. Use the guiding questions on p. 341 (TE Manual). For the 4th question on p. 341, the teacher will complete tens/ones language below. Put this information on an anchor chart for students to reference the format throughout the GCG. 3 tens + 0 ones 2 tens + 5 ones 5 tens + 5 ones = 55 Building Conceptual Knowledge: Go Math Model and Draw p. 342 and On Your Own p. 343 #s 2-4. With these problems, students will build a base ten model on the place value mat. Similar to the engage, the teacher will probe students about the place value in the tens and ones and record this information in the format above. It is critical teachers model this format for each base ten model. This format allows students to add any two digit numbers without regrouping/trading. Students will be expected to write this format as the GCG progresses.

Day 1 Continued… Essential Question: How can you model tens and ones to add two digit numbers? Closure: Go Math Share and Show p. 342 #1. Students will build a base ten model and draw a quick pic of the model. Encourage students to complete the base ten language next to the model. It is already completed for the tens and ones for each addend. Even though students did not complete their base ten language during the lesson, this piece will help you drive instruction for day 2. By the end of Day 1, students should be able to create a base ten model on the place value mat and communicate to the teacher the place value in tens and ones.

Day 2 Essential Question: How can you draw a quick pic to add two digit numbers? This day will be an extension to Day 1. Students are expected to draw quick pics for the base ten model. It is expected that students will start to record the base ten language that was modeled by the teacher on Day 1. Engage: Go Math Lesson 8.8, Problem Solving p. 340 # 7 & 9. Pose these problems to students without the the book. Students will draw a quick pic and start recording the base ten language format. If needed, students can build the base ten model and draw a quick pic from the base ten blocks. Building Conceptual Knowledge: Use numeral cards to have students select 2- two digit numbers. Each numeral card will be the addend and students will add both addends together. Students will draw a quick pic and record the base ten language in a math journal. As the students are working on this task, the teacher should monitor student work to determine if the whole group needs reteaching or if a small group of students need remediation. If a few of your students are spending more time on the writing of words versus the place value mathematics, write the format on paper and the student will complete the number of tens, ones, and values. By the end of Day 2, students should be drawing quick pics for adding two digit numbers. Students should also be recording the values in base ten format presented on Day 1.

Day 3 Essential Question: How can you use a hundreds chart to add two digit numbers? This day will focus on the place value concepts when adding two digit numbers using the tool: hundreds chart. Engage: Pose the following problem solving scenario to your students: Ahkeem has 32 crayons. His big brother gives him 25 crayons. How many crayons does Ahkeem have now? Have students solve using base ten blocks/quick pics first. Discuss what does the model represent and place value for the tens and ones. Then provide students with a hundred chart and model the scenario on the hundred chart. Discuss what is similar/different among the two strategies. Building Conceptual Knowledge: Go Math Lesson 8.8, Try Another Problem p. 346 #1 & 2. Pose the scenarios to students and have them solve for the sum using the hundreds chart. The teacher should probe students as they are completing the hundreds chart about the place values in the tens and ones. Independent Practice: Hundreds Chart Two Digit Practice Students will use the hundreds chart to solve the given problems. Each problem will have a hundreds chart so students will be able to track their thinking. By the end of Day 3, students should be able to use a hundreds chart to add two digit numbers.

Day 4 Essential Question: How can you use a number line to add two digit numbers? This day will focus on the place value concepts when adding two digit numbers using the tool: open number line. Engage: Pose the following problem solving scenario to your students: I have 34 small shells and 14 big shells. How many shells do I have? Have students solve using the hundred chart first. Discuss how did the students use the hundred chart and the place values for the tens and ones. Ask students, “How can I solve this problem using an open number line?” Teacher should model the open number line for this scenario. Building Conceptual Knowledge: Go Math Share and Show p. 347 #s 3,4,5. Pose the scenarios to students and have them solve for the sum using an open number line. The teacher should probe students as they are completing the open number line about the place value connections. Independent Practice: Open Number Line Two Digit Practice Students will use the open number line to solve the given problems. Each problem will have an open number line so students will be able to track their thinking. By the end of Day 4, students should be able to use an open number line to add two digit numbers.