Arrays: Multiplication You Can SEE!

What You'll Learn

• Rows go across (side to side) and columns go up and down
• The number of rows times the number of columns equals the total
• Turning an array sideways swaps the rows and columns but the total stays the same (commutative property)
• Arrays are everywhere in real life: egg cartons, muffin tins, stamp sheets
• The word "array" comes from Latin meaning "to put in order"

Words to Know

Array

A grid of things lined up in equal rows and equal columns

A muffin tin with 3 rows of 4 muffins is an array.

Row

A line of objects going across, side to side

The top row of cupcakes has 4 in it.

Column

A line of objects going up and down

Each column in the egg carton has 2 eggs.

Factor

A number you multiply together with another number

In 3×4=12, the numbers 3 and 4 are the factors.

Commutative Property

You can swap the order when multiplying and get the same answer

3×4 and 4×3 both equal 12, thanks to the commutative property.

Product

The answer you get when you multiply two numbers

The product of 3 and 4 is 12.

Check What You Learned

Fun Facts

• An array is a set of objects arranged in rows and columns, where each row has the same number of objects and each column has the same number of objects.

  Source: Common Core Standards Initiative, 3.OA.A.1

• In a multiplication array, the number of rows times the number of columns equals the total number of objects: 3 rows × 4 columns = 12 total.

  Source: Eureka Math/EngageNY Grade 3 Module 1

• Turning an array 90 degrees swaps the rows and columns but the total stays the same, demonstrating the commutative property of multiplication: 3×4 = 4×3 = 12.

  Source: National Council of Teachers of Mathematics, Principles and Standards

• The word "array" comes from the Latin word "arrangere," meaning "to put in order" or "to arrange."

  Source: Online Etymology Dictionary

• Egg cartons holding 12 eggs are a common real-world array with 2 rows of 6 columns.

  Source: Eureka Math/EngageNY Grade 3 real-world examples

• A standard muffin tin with 12 cups is arranged as a 3×4 or 2×6 array.

  Source: YouCubed, Stanford University math education resources