The purpose of this lesson is for students to add 2 two-digit numbers using methods based on place value.
In the previous lesson, students added 2 two-digit numbers with composing a ten, in a way that made sense to them. This lesson focuses on adding tens and tens and ones and ones. This method is important because it sets students up to add multi-digit numbers in later grades. Students apply what they learned about the commutative and associative properties to see that it doesn’t matter if they add tens and tens first or ones and ones first.
- Add two-digit numbers by adding tens and tens and ones and ones.
- Sumemos números de dos dígitos.
- Create two separate posters that show base-ten drawings of 34 and 57. Leave space to write equations underneath the drawings.
- Each group of 2 needs a set of digit cards from the previous center, Number Puzzles.
Teacher Reflection Questions
In what ways does the work of this lesson lay the foundation for student understanding of the standard algorithm for addition, which will be used in later grades?