Question

Matt is showing his work in simplifying (6.2 − 1.6) − 4.4 + 7.8. Identify any error in his work or reasoning.
Step 1: (6.2 − 1.6) − 4.4 + 7.8
Step 2: 6.2 + (−1.6 − 4.4) + 7.8 (commutative property)
Step 3: 6.2 − 6 + 7.8
Step 4: 6.2 + 7.8 − 6 (commutative property)
Step 5: 14 − 6 = 8

Answer 1

Thoughts? As a major hint, moving the placement of brackets would be the associative property not the commutative property. With that in mind, which step do you think has the incorrect reasoning for it?