Arlene is showing her work in simplifying −7.9 + 8.2 − 3.4 + 2.1. identify any errors in her work or in her reasoning. write feedback to arlene explaining the mistake she made and how to correct her work.
the way she did it was
step work reasoning
−7.9 + 8.2 − 3.4 + 2.1 original problem
1 −7.9 + 8.2 + (−3.4) + 2.1 additive inverse
2 −7.9 + (−3.4) + 8.2 + 2.1 associative property
3 (−7.9 + (−3.4)) + (8.2 + 2.1) commutative property
4 −11.3 + 10.3 simplify
5 −1 simplify