Adding With Arrays

Lesson Plan - Get It!

Audio:

• Did you take a mental picture of your dresser or shelving unit?

Draw the dresser or shelf on a blank sheet of paper. It will probably look something like the picture below.

This is called an array.

Arrays are tools to make it easier to count and add. When you are older, you can use an array to help you multiply.

An array is made up of rows and columns.

• Have you ever sat in a row, maybe at a movie theater, on a bus, or at a sporting event?

When you sit in a row, it is easier to see things. Rows also create organization.

Rows always go across.

Columns go up and down to help support the array, just like columns in a building help support the roof.

Practice writing addition equations to find the number of objects in an array.

In one of your dresser drawers, you have shirts folded and arranged in 2 rows and 4 columns.

You can find the total number of shirts in this drawer using this array. You can use two expressions to solve this problem.

First, look at the rows.

There are 2 rows of shirts. If you count the first row, there are 4 shirts. Each row has 4 shirts. Add the rows together to find the total number of shirts.

Row + Row = Total

(Notice 2 rows are being added because that is how many rows are in this array.)

4 + 4 = 8

Next, look at the columns.

This time, count the number of columns. There are 4 columns. In each column, there are 2 shirts. Add the columns together to find the total number of shirts.

Column + Column + Column + Column = Total

(Notice 4 columns are being added because that is how many columns are in this array.)

2 + 2 + 2 + 2 = 8

Both expressions answered 8 shirts in the drawer!

• Can you think of other places you have seen arrays?

Watch the video below to see some places where you see arrays every day.

After watching the video, continue to the Got It? section to jump into arrays!