- Second Grade
- 45 minutes
- Standards: 2.OA.C.4
In this lesson, your students will use repeated addition to find the total number of objects in arrays. This lesson will help your students build upon the skills needed to learn multiplication.
Students will be able to describe an array using repeated addition.
Introduction (5 minutes)
- Give each student 25 counters.
- Ask your students to make 8 groups with 3 counters in each group.
- Direct your students to count by threes.
- Ask them to identify how many counters there are altogether.
- Write an equation to show this. For example: 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3.
- Tell students that today they are going to describe an array, or an ordered display, using number sentences.
Explicit Instruction/Teacher Modeling (10 minutes)
- Draw a 5-by-5 array on the board.
- Read aloud the following problem: Maria has 4 treat bags with 5 cookies in each bag. How many cookies are there in all?
- Model the problem by shading in 4 rows and 5 columns on the board.
- Ask students what strategy they could use to find the total number of cookies.
- Ask students if the answer would change if the numbers were turned around (if there were 5 rows and 4 columns). Explain that this does not change the answer.
- Give students a problem such as: Tiki has 4 rows of cars with 2 cars in each row. How many cars are there?
- Model the problem on the board by drawing it out.
- Use repeated addition to write a number sentence.
Guided Practice/Interactive Modeling (10 minutes)
- Draw other arrays on the board, and have students use counters to practice solving and writing addition sentences for each array.
Independent Working Time (10 minutes)
- Have students complete the Array Practice worksheet on their own.
- Enrichment: Give advanced students 35 counters. Have them create as many different arrays as they can with all 35 counters. Then, have them write number sentences for each array.
- Support: Give students manipulatives to complete their arrays.
Related Books and/or Media
Assessment (5 minutes)
- Have students answer the following problem: There are 4 rows of chairs with 6 chairs in each row. How many chairs are there in all?
- Circulate and observe students as they work.
Review and Closing (5 minutes)
- Ask a volunteer what an array is.
- Have students provide real-life examples of arrays, such as bookshelves and egg cartons.
- Watch the Real Life Arrays video.