Question

Owen solves a subtraction problem using the Associative Property. First, he groups 5,709 and 3,709 together, then subtracts their difference from 18,724. Do you agree with Owen's reasoning?

A. Yes. Owen correctly used the Associative Property.
B. Yes. Owen correctly subtracted the grouped numbers.
C. No. Owen cannot change the groupings of numbers to subtract. He should use counting on instead.
D. No. Owen cannot change the order of numbers to subtract. He should use compensation instead

Answer 1

Owen's reasoning is incorrect because he used the Associative Property of Addition instead of the Associative Property of Subtraction.

Step-by-step explanation:

The student's reasoning is incorrect. Owen used the Associative Property of Addition, not the Associative Property of Subtraction. The Associative Property of Addition states that the grouping of numbers does not affect the sum. However, the Associative Property of Subtraction does not exist. Owen cannot change the grouping of the numbers to subtract. Instead, he should have subtracted 3,709 from 5,709 first, and then subtracted the result from 18,724, following the correct order of operations for subtraction.

For example, using the correct method, the calculation would be: 5,709 - 3,709 = 2,000. Then, 18,724 - 2,000 = 16,724.

Therefore, the correct answer is option C. No, Owen cannot change the groupings of numbers to subtract. He should use counting on instead.