Question 87

The activity reinforces students' understanding of the inverse relationship of addition and subtraction and the commutative property of addition.

The teacher's activity highlights the connections between addition and subtraction, demonstrating how they are inversely related, as well as showing that the order of addition does not affect the sum.

A) The inverse relationship of addition and subtraction

This option is correct because the number sentences illustrate how addition and subtraction are inverse operations. For example, the equations 7 + 8 = 15 and 15 - 8 = 7 show that adding 8 to 7 gives a total of 15, and subtracting 8 from 15 returns to 7, reinforcing the concept of inverse relationships.

B) The commutative property of addition

This option is also correct as it is demonstrated through the sentences 7 + 8 = 15 and 8 + 7 = 15. The results of both additions are the same regardless of the order of the addends, clearly illustrating the commutative property of addition.

C) The identity property of subtraction

This option is incorrect because the identity property pertains to addition, specifically that adding zero to a number does not change its value, and there is no direct application of this property in the number sentences provided.

D) The associative property of addition

This option is incorrect as the associative property states that the way numbers are grouped in addition does not affect the sum. The provided number sentences do not illustrate grouping or changing the arrangement of addends, thus not demonstrating this property.

Conclusion

The activity effectively illustrates the inverse relationship of addition and subtraction alongside the commutative property, as evidenced by the provided equations. Options C and D fail to apply to the context of the activity, as they pertain to different mathematical properties not represented in the teacher's examples. Thus, A and B are the only correct answers that align with the learning objectives.