Come "Array" With Us
Students will use addition to find the total number of objects arranged in a rectangular array. Students will write an equation to express the total as a sum of equal addends
- Pass out math journals or lined sheets of paper, and ask students if they know what an array is. Give students a few minutes to write their response, and tell them to be prepared to share with the class.
- As students share responses, write down key points on the whiteboard or chart paper. For example: Arrays = rows, columns, rectangular, equal groups, addition, etc.
- Write down the term array on the board or chart paper, and define it as an arrangement of objects, pictures, or numbers in columns and rows.
- Have students recopy the definition in their journal or on lined paper. This will allow students to make a comparison to their initial response.
- Next, draw an example of an array for students, and have them copy it in their notes.
- Tell students that based on the definition of an array, they will do a school scavenger hunt to find real life examples of arrays. In addition, they will take a picture of their array, identify the rows and columns, and write and solve for a matching addition equation.
Explicit Instruction/Teacher Modeling(10 minutes)
- Walk around the classroom to model looking for an array while showing the class how to be respectful to personal belongings.
- Find an object in the classroom that represents an array. Find something unusual, like tiles on the ceiling, a wire basket, or the back of a chair. Using a digital camera or iPad, take a picture of the object while identifying your example to the class. See Appendix A for examples.
- On the board, draw an array that represents your object. Use dots or X’s. Tell students that the first thing you want to identify are the number of rows in the array, and then the number of columns.
- Remind students that rows go across or left and right. With a red marker, draw an arrow going across each row.
- Next, review with students that columns tell how many objects are in each row. They go up and down; just like columns on a building.
- Ask a student volunteer to identify how many rows are in your array, and to answer how many objects are in each row. Write this information in a complete sentence.
- For example:
This array has 2 rows with 5 objects in each row. X X X X X X X X X X
- Next, write the number of objects in each row at the end of the red arrows that you drew on the board. Point to these numbers and tell students they are called addends. Then, transfer this information and write a repeating addition problem showing the addends and sum. Example: 5+5=10.
- Inform students that they will be placed in pairs. Each pair is responsible for finding an array no more than 5 rows and 5 columns. They will take a digital picture, write a sentence to identify rows and columns, and write an addition equation. Remind students that all three pieces of information will be presented on a slideshow slide for the class.
Guided Practice/Interactive Modeling(10 minutes)
- To begin, review classroom expectations with the class, and remind pairs of students about cooperation, as there will be lots of movement.
- Do a practice round. Have pairs walk about the classroom in search of some arrays. Some examples would be cubbies, box cases, posters, and a calendar.
- After using a class signal to pause students, call on one pair of students to share where they found an array.
- Using a digital camera or iPad, have the students take a picture. Tell students to include at least one member of their team in the picture, as this makes it easier to identify whose work is whose when it comes to working on the slideshow slide.
- Ask the pair of students to identify the number of rows and columns, and write an addition sentence on the board with its sum. Encourage students to share responsibility when working together.
- Share with students how their pictures will be downloaded onto a slideshow presentation and that each pair is responsible for including their written information on their slide.
- Tell the students that they will have more than one opportunity to locate arrays, as the lesson can include a search within the school and outside on the school grounds.
- Remind the class that all slides will be placed together to produce a slideshow presentation on arrays and will serve as a learning tool.
Independent Working Time(25 minutes)
- Before beginning, remind students about school expectations.
- Each pair of students will begin their hunt for arrays in the location of your choice, or students will hunt in two different locations for 10 minutes each.
- If a class set of digital cameras or iPads are available, use one per pair of students.
- If the classroom has one camera, the pair of students should ask the teacher to take the picture, so the teacher will know where the camera is at all times.
- Remind students to solve and write their sentences and addition equation for their array before working on their slide.
- Enrichment: To challenge students, ask them to find arrays larger than 5 by 5. Ask students to find additional arrays on their hunt and write math problems or questions to go along with them.
- Support: For students who need support, closely monitor or pair with students who have a clear understanding on arrays. Teach movements to support the difference between rows and columns.
- Monitor students during their independent work time, and provide support when necessary.
- Review pictures of arrays and student written work.
- Optional homework assignment: Ask students to find arrays at home and send a picture to your email.
Review and Closing(5 minutes)
- Identify arrays in the classroom, and ask review questions on each. For instance: “How many rows are in this array?” “What is the addition equation that matches this array?” “How many columns are present?”
- Have students share what they learned in math today.