Model and Draw Addition with 3-Digit Numbers Unit of Study 6: 3-digit Addition and Subtraction Global Concept Guide: 1 of 4

Content Development  The purpose of this GCG is to focus on modeling and drawing pictures to add three digit numbers.  A major misconception is that students do not need to use base-ten blocks because they have used them in the last three units. Students need to have a conceptual understanding of when to regroup, why we regroup, and how we track our regrouping. These steps may be modeled or drawn using quick pictures.  By the end of this unit we want students to transfer their models into quick pictures.  Remember to have students think of what a reasonable answer might be prior to solving!  Students should be comfortable with checking their solution using a different strategy including inverse operations.

Regroup Trade Exchange Vocabulary  Remember to use the following words throughout the unit.

Addition Properties According to the standard~ MAFS.2NBT.2.9- Explain why addition and subtraction strategies work, using place value and the properties of operations. Two properties of operations that students should be using are: Associative property- grouping addends together to make the addition more efficient ~ Strategies that support the associative property are doubles +/- 1. Commutative property- switching the order of the addends to make the math more efficient. A strategy that supports this is adding with the greater number first. If I have 2 + 8=_____, I would use the commutative property and solve using 8+2 because it is more efficient to start with 8 and add 2. Students should be able to explain the properties but do not need to know the names of the properties.

Day 1  Essential question: How can I use a number line to add 3-digit numbers?  Number line Learn Zillion video ~ Quick code~ LZ Students will focus on putting numbers into expanded form to subtract.Learn Zillion Sample engage question:  Sally McSneezy used 179 tissues on Monday and 248 on Tuesday. How many tissues did Sally use? Have students solve this problem using the number line. Students should recognize by starting with 248 (the greater addend) it will be more efficient. Then they decompose the 179 and add it on. Allow students to share, but scaffold their solution strategies to the more efficient. Two possible solutions: ProblemsProblems you could use. By the end of Day 1, students will be able to use a number line to add 3-digit numbers. Possible daily journal responses.journal

Day 2  Essential question: How can I use models to add 3-digit numbers?  Students will use base-ten blocks to solve various word problems focused on addition. Students should not be expected to record on this day.  Sample engage question:  Sally McSneezy used 179 tissues on Monday and 248 on Tuesday. How many tissues did Sally use? (You must be logged in as a teacher to view this video.  Have students solve this same engage question from yesterday using base- ten blocks. The focus should be how the strategies are the same or different.  Problems to use. These are the same problems as yesterday. Students should make connections between the similarities and differences between solving with two different strategies. Problems  By the end of Day 2, students will be able to model the addition of 3-digit numbers. Possible daily journal responses.journal ClickClick to view a demonstration of 3-digit addition with modeling.

Day 3  Essential question: How can I connect my models of 3-digit addition to drawings?  Day 3 should be focused on connecting the actions that students are doing with their base-ten blocks to pictorial representations of those same actions.  Sample engage question:  Kumba had 143 boys and 89 girls riding. How many children were on the ride? (You must be logged in as a teacher to view this video.)  Problems you may use for students to model and draw quick pictures. Problems  By the end of Day 3, students will be able to connect their models of 3-digit addition to drawings. Possible daily journal responses.journal ClickClick to view a demonstration of 3-digit addition with quick pics.

Day 4  Essential question: How can I record my steps when adding 3-digit numbers?  Students should be solving using base-ten blocks or quick pictures As they solve, they should record their steps using numbers.  Sample engage question:  Mr. Skittles has 245 pieces of red candy and 179 pieces of blue candy. How much candy does Mr. Skittles have? (You must be logged in as a teacher to view this video.)  Problems you can use for students to record the steps while modeling or drawing pictures. Problems  By the end of Day 4, students will be able to record my steps when adding 3- digit numbers. Possible daily journal responses.journal ClickClick to view a demonstration of recording 3-digit addition.

Day 5  Essential question: How can I explain the steps when adding 3-digit numbers?  This could be a good day for differentiation. Students may explain their steps using pictures or words. Some questions you may ask: ?Is the value of your number the same after you regrouped? ?Why is it more efficient to begin combining numbers in the ones place? ?How do you know when you have to regroup? ?Given the following table, students should be able to explain how all 3 numbers are equivalent.  Additional problems you can use. Additional problems  By the end of Day 5, students should be able to explain their steps when adding 3- digit numbers. Possible daily journal response.journal  By the end of Day 5, students will be able to explain the steps when adding 3- digit numbers. Possible daily journal responses.journal HTO

Enrich/Reteach/Intervention Reteach  If students are struggling with adding three digit numbers, you may want them to add and subtract three digit numbers without regrouping and ease into regrouping with base-ten blocks. (You must be logged in as a teacher to view these video.) *These videos may be shown To students. Enrich  Enrich ideas from TE p. 281B  Enrich ~ E56  Give students a number such as 679. They should represent in all the possible ways in a H,T,O chart.  Give students an equation such as and they write story problems based on the given equation.  Students work in pairs. 1 st player rolls 6 dice and create 2 3-digit numbers that when combined makes a sum closest to 1,000 without going over. Player 2 repeats these steps. Whoever has the sum closest to 1,000 without going over, gets 1 point. ClickClick to view a demonstration of 3-digit addition with modeling. ClickClick to view a demonstration of 3-digit addition with quick pics. ClickClick to view a demonstration of recording 3-digit addition.