 Lesson plan

# Adding by grouping tens into hundreds

teaches Common Core State Standards MP7 http://corestandards.org/Math/Practice/MP7
teaches Common Core State Standards 2.NBT.B.6 http://corestandards.org/Math/Content/2/NBT/B/6
teaches Common Core State Standards MP8 http://corestandards.org/Math/Practice/MP8
teaches Common Core State Standards 2.NBT.B.7 http://corestandards.org/Math/Content/2/NBT/B/7

# Adding by grouping tens into hundreds

Big Ideas: Numbers can be decomposed into smaller units and the smaller units can be reorganized to make equivalent numbers. Concrete models or drawings can be used to represent addition or subtraction within 1000. In this lesson, students will add within 1000 by organizing tens into hundreds. Students can justify their solutions using base ten representations to compose 10s to form 100s. Students have previously combined ones to form tens when adding 2-digit numbers (2.NBT.5). Students will apply this understanding, along with their three-digit place value understandings (2.NBT.1-4), to add two and three-digit numbers. Vocabulary: Add, sum, hundreds, tens, ones, base ten, combine, group, organize Special Materials: Base ten blocks - hundreds, tens, ones