In this unit, students who have previously studied the meanings of addition use the properties of addition to help them learn addition facts and to master the addition tables. The unit is most appropriate for students of grades 1 and 2. The ability to name the sum of two one-digit numbers with speed and accuracy is an important accomplishment. This skill allows students to focus on multistep algorithms and to compute the answers to problems.
Addition properties explored in this unit include
the order property, the additive identity, and the results of adding by zero. The most effective and efficient way to help students learn addition facts is to help them build an understanding of the operation, encourage them to use the helpful features of the number system, and give them interesting activities that foster retention.
Individual Lessons
Lesson 1 - Finding Addition Patterns
A game encourages students to find the sums of two one-digit numbers. Students explore commutativity and examine addition patterns. Then they record known facts on a personal addition chart.
Lesson 2 - Finding Sums to Six
In this lesson, students discover the role of the additive identity and explore sums to six. They continue to complete their personal addition charts.
Lesson 3 - Some Special Sums
Students practice doubles and doubles-plus-one addition facts. They record their current level of mastery of the addition facts on their personal addition charts.
Lesson 4 - Addend Pairs to 12
Students practice their addition facts for sums up to 12 by playing a game. They add to their personal addition charts. Students are encouraged to practice the facts that they have not yet mastered. Finally, triangular flash cards help students practice addition facts.
Lesson 5 - Wrapping up the Unit
In this final lesson of the unit, students display their knowledge of properties of objects for sorting and creating patterns. They also demonstrate an understanding of commutativity and model addition and subtraction of whole numbers using different representations.
