Creating Arrays

Creating Arrays

Arrays serve a variety of roles in math instruction. They illustrate multiplication and division. You can use 10 by 10 arrays and 1 by 10 arrays to demonstrate whole number and decimal place values. Arrays can also be used to represent fractions. Spreadsheets present an exciting alternative to the traditional graph paper for generating and manipulating arrays. With a spreadsheet it is possible to make "electronic graph paper" so that arrays can be displayed and manipulated. You can create an array by using Excel's tools that create borders and fill cells with a variety of colors. by dragging cells on the screen, you can rearrange the arrays. Arrays will be used in a variety of Math Concepts lessons.

Teacher Note: You can use this file for array activities. These files are preformatted spreadsheets of three different sizes. If you want to learn how to format a spreadsheet for arrays, read the steps below.

Steps in Formatting Arrays

This is a 2 x 4 array (2 rows and 4 columns)

1. Change the column reference from letters to numbers (optional)

Do this step only if you want column headings to be numbers rather than letters. To do this, select TOOLS from the menu bar, OPTIONS, and then GENERAL. Change REFERENCE STYLE from A1 to R1C1.

By changing the column headings to numbers, students will be able to "count" the number sides of the array. This change applies to everything you do in Excel from then on. Be sure to change it back to A1 before you do other spreadsheet work.

2. Make the columns smaller

Click in the box at the very upper left hand corner of the spreadsheet. This will select all of your cells.
Select FORMAT, COLUMNS, WIDTH, and change the number to 2 or 3. You can also change the widths of the columns by changing the viewing area (See step 3).

3. Make more viewing area

Go to VIEW in the menu options. Select ZOOM and reduce the size of the spreadsheet to 75% or less. This will allow you to make larger arrays and perform more rearrangements.

Steps in Using Arrays

1. Highlight the array.

Click in the upper left hand corner of the first cell that you want to use for your array.
Drag diagonally to the last cell in the lower right hand corner.

2. Color the array

Make sure that all the cells you want to color are highlighted.
Click on the color button (tilted paint can).
Click in the color box. Your grid lines will disappear.

3. Put in a grid

Click on the border button (next to color button).
Select grid with cross lines and a surrounding border.

4. To move cells in arrays

You can move cells around the spreadsheet by clicking and dragging across the cells you select, and moving the group of cells to another place on the spreadsheet. Experiment with this feature.