Adding and Subtracting Whole Numbers Unit of Study: 5 Global Concept Guide: 4 of 4

Content Development  Students should grow comfortable solving addition and subtraction problems using numbers through hundred thousands (6-digits).  Build conceptual understanding of regrouping. Avoid simply showing the algorithm before regrouping is understood and avoid using the term “borrow”.  Make sure to teach addition and subtraction together showing they are inverse operations, not teaching each in isolation.  Provide students with multiple opportunities to use large numbers in both story problems and tables when adding and subtracting.

Day 1  Students should be able to create models to show addition and subtraction problems.  Use both base-ten blocks and drawing to model numbers. Example: Lucy represented the number1,234 with in a written model. Ming drew a similar model representing the number 1,355. What is the sum of their models?

Day 2  Make sure to provide opportunities for students to conceptually understand regrouping. Allowing students to use base-ten blocks to model regrouping, helps them build understanding.  Avoid simply showing the algorithm before regrouping is understood.  Provide students with real world problems to practice regrouping.

Replay Slide

Replay Slide

Day 3 and Day 4  Make sure to teach addition and subtraction together and not in isolation.  When using strategies for addition and subtraction start with 4-digit numbers and use this to build into numbers through hundred thousands.  Provide opportunities for students to see multiple strategies when adding and subtracting larger numbers: Break Apart Strategy (Decomposing)- numbers written in expanded form and each place value is added or subtracted Place Value Method- The most common way to add and subtract going digit-by-digit with in the number = 328

Day 5  Students should be able to apply the most efficient strategy when solving problems.  Student’s should make the connection that addition and subtraction are inverse operations.  Provide students with facts and solutions and have them identify the question and/or operation that could be used to arrive at the solution. Example: Facts-There are 7,700 lakes in Florida. There are 4,500 lakes in Michigan. Solution- 3,200 lakes What question could be asked to get this solution, and what operation was used?

Enrich/Reteach/Intervention  Reteach/Intervention: Using a selection of problems and have students make numbers with base-ten blocks and have them model regrouping. Allow student to become successful with modeling and move to pictoral representations.  If student’s are struggling with the alignment of digits when adding or subtracting, have students utilize grid paper to keep the digits within the correct place value position. (Hint: Students can also turn notebooks side ways providing columns for this as well)

Enrich/Reteach/Intervention  Enrich- Give students riddles (CPALMS lesson found on GCG) and have them use the clues to discover the number. Also have students create their own riddles when given a number.