Commutativity Math Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

easy
If \(13 + 27 = 40\), what is \(27 + 13\)? Explain without calculating.

Solution

  1. 1
    By commutativity: \(a + b = b + a\).
  2. 2
    So \(27 + 13 = 13 + 27 = 40\).
  3. 3
    No calculation needed.

Answer

40
The commutative property means swapping the order of addends doesn't change the sum.

About Commutativity

A property where swapping the order of two operands does not change the result: a ⋆ b=b ⋆ aa \ \star\ b = b\ \star\ a.

Learn more about Commutativity →

More Commutativity Examples

Example 1 easy

Show that (6 + 9 = 9 + 6). Does the order of adding matter?

Example 2 medium

Verify that (4 times 7 = 7 times 4) using a rectangular array. Explain what changes and what stays t

Example 4 medium

Does commutativity work for subtraction? Check with (10 - 3) and (3 - 10).

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