Andrew is showing his work in simplifying −4.5 + 4.2 + 5.6 − 7.3. Identify any errors in his work or in his reasoning. Write feedback to Andrew explaining the mistake he made and how to correct his work.

Step Work Reasoning
−4.5 + 4.2 + 5.6 − 7.3 Original problem
1 −4.5 + 4.2 + 5.6 + (−7.3) Additive inverse
2 −4.5 + (−7.3) + 4.2 + 5.6 Commutative property
3 (−4.5 + (−7.3)) + (4.2 + 5.6) Associative property
4 −11.8 + 9.8 Simplify
5 −21.6 Simplify

Question

Andrew is showing his work in simplifying −4.5 + 4.2 + 5.6 − 7.3. Identify any errors in his work or in his reasoning. Write feedback to Andrew explaining the mistake he made and how to correct his work.

Step	Work	Reasoning
 	−4.5 + 4.2 + 5.6 − 7.3	Original problem
1	−4.5 + 4.2 + 5.6 + (−7.3)	Additive inverse
2	−4.5 + (−7.3) + 4.2 + 5.6	Commutative property
3	(−4.5 + (−7.3)) + (4.2 + 5.6)	Associative property
4	−11.8 + 9.8	Simplify
5	−21.6	Simplify

Vocaloid · Answer

Everything is correct **until** steps 4-5. Can you see where he made a mistake turning -11.9 + 9.8 into -21.6? it has something to do with positive/negative signs.