Tom is showing his work in simplifying (5.2 - 8.5) - 0.5 + 6.8. In which step did Tom make an error?

Step 1:: (5.2 - 8.5) - 0.5 + 6.8

Step 2: 5.2 + (-8.5 - 0.5) + 6.8 (distributive property)

Step 3: 5.2 - 9 + 6.8

Step 4: 5.2 + 6.8 - 9 (commutative property)

Step 5: 12 - 9 = 3
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Step 2; he wrote distributive instead of commutative

Step 2; he wrote distributive instead of associative

Step 4; he wrote commutative instead of associative

Step 4; he wrote commutative instead of distributive