Question

Blake is showing his work in simplifying (4.6 − 9.2) − 0.8 + 5.4. Identify any error in his work or reasoning.

Step 1: (4.6 − 9.2) − 0.8 + 5.4
Step 2: 4.6 + (− 9.2 − 0.8) + 5.4 (associative property)
Step 3: 4.6 − 10 + 5.4
Step 4: 4.6 + 5.4 − 10 (associative property)
Step 5: 10 − 10 = 0
A.He wrote associative instead of commutative in Step 4.
B. He wrote associative instead of commutative in Step 2.
C. He wrote associative instead of distributive in Step 4.
D. He wrote associative instead of distributive in Step 2.

Answer 1

Based from Blake's step-by-step solution, the error in his work is stated by choice A. He wrote associative instead of commutative in Step 4. In Step 4, he changed the position of -10 and +5.4. This action can be done due to the commutative property of addition which states that numbers can be added in any order. Whereas, the associative property of addition states that numbers can be added regardless of the way they are grouped.