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Commutative property of multiplication

Commutative property of multiplication

The Commutative Property of Multiplication states that changing the order of the factors in a multiplication operation does not change the product. In other words, if aa and bb are any two numbers, then:

a×b=b×aa \times b = b \times a

For example, 3×4=4×3=123 \times 4 = 4 \times 3 = 12. This property is fundamental in arithmetic and underlies many mathematical concepts and operations.

Part 1: Commutative property of multiplication

Sal explores what happens when we multiply numbers in different orders, for example 3x5 and 5x3.

Key Points of the Commutative Property of Multiplication:

  1. Definition: The commutative property of multiplication states that changing the order of the factors does not change the product. In mathematical terms, a×b=b×aa \times b = b \times a.

  2. Examples:

    • 3×5=153 \times 5 = 15 and 5×3=155 \times 3 = 15
    • 7×2=147 \times 2 = 14 and 2×7=142 \times 7 = 14
  3. Visual Representation: Illustrate the property with arrays and grouping to show that rearranging factors leads to the same total.

  4. Application: This property simplifies multiplication calculations and helps in mental math by allowing for rearrangement of numbers to make calculations easier.

  5. Relation to Other Properties: The commutative property applies to addition as well, emphasizing a broader principle in arithmetic operations.

  6. Importance in Algebra: Understanding this property is foundational for solving equations and manipulating expressions in algebra.

By grasping these key points, students can effectively utilize the commutative property in various mathematical contexts.