Arrays With Egg Cartons, Candy Corn and Windows: Hands-On Multiplication for Grades 2–3

Short answer: Use what is already on your shelf: egg cartons for 2 × 6, grid paper or sticky notes for candy corn rows, and a window grid drawn on the board. Kids build the array, name the rows, turn it, and only then write the multiplication sentence.

Egg cartons are ready-made arrays

A 12-cell carton is 2 rows of 6. Give pairs one carton and a handful of counters, and ask them to fill it. Write 2 × 6 = 12 together. Then have pairs tip the twelve counters out and lay them on the desk as 3 rows of 4. Same twelve counters, different shape.

Ask the question that matters: “What happens if I turn it?” Rows become columns and 3 × 4 becomes 4 × 3. Twelve either way.

Candy corn without the candy

Real candy gets eaten, and then you have no array. Draw or cut candy corn shapes from orange and yellow paper and let kids lay out 5 rows of 5 on a desk. They’ll notice that turning 5 × 5 gives the same array, which is a nice little surprise after 3 × 4.

For a quick whole-class version, stick sticky notes on the board in 3 rows of 5 and ask for the sentence. Then rearrange them to 5 rows of 3 and ask what changed and what didn’t. Fifteen both times.

Windows on a house

Draw a house with a grid of windows: 4 rows, 3 windows in each row. Say the rule out loud: the first number is the rows, the second is how many in each row. Have a student trace each row with a finger before anyone writes.

1. Count the windows by rows: 3, 6, 9, 12.
2. Write the repeated addition, 3 + 3 + 3 + 3.
3. Write 4 × 3 = 12.
4. Turn the house and write 3 × 4 = 12.
5. Ask: “I know there are 12 windows. What other houses could have 12?” Look for 2 × 6 and 6 × 2.

Common snags

Kids will count the decoration. A pumpkin sticker in the corner is not a window. Tell them early which things count and which don’t. Others will mix up rows and columns, which is why the one-sentence rule stays on the board all week.

A ten-minute whole-class version

No cartons? Run it on the board. Draw a grid, ask for a volunteer to name rows and columns, and let the class write the sentence on mini whiteboards. Then ask three kids for three different arrays with the same total. With 12, you will usually get 2 × 6, 3 × 4, and one brave 1 × 12.

Finish with an exit ticket: draw an array for 15 and write two multiplication sentences for it. You will see right away who still mixes up the number of rows with the number in each row.

When you want the pages already made

Drawing precise window grids and writing the follow-up questions is where the time goes. Haunted House Math: Arrays & Fact Families has labeled window arrays, a learning block on turning arrays (including 3 × 4 = 4 × 3 and the 5 × 5 surprise), and answers in the teacher guide. Its decorative illustrations are marked as not being counting models, so only the labeled arrays are counted. Overview on the Halloween arrays and multiplication page.

FAQ

Are egg cartons really useful for teaching arrays?

Yes. A 12-cell carton is 2 rows of 6, so it shows an array without any drawing. Cut cartons into 2 x 3 or 2 x 4 pieces to show smaller arrays, or use an 18-cell carton for 3 rows of 6.

What is the difference between rows and columns in an array?

Rows go across and columns go up and down. Pick a convention, such as the first factor being the number of rows, and use it all week so students don't swap them.

Which grades is this for?

Mostly Grades 2 and 3. Second graders build arrays and write repeated addition. Third graders connect them to multiplication sentences and the commutative idea that 3 x 4 equals 4 x 3.

Keep reading

• Halloween Math Activities That Actually Practice Multiplication
• How to Run Halloween Learning Stations Without Chaos: A Three-Period Plan