Matt is showing his work in simplifying (6.2 − 1.6) − 4.4 + 7.8. Identify any error in his work or reasoning. Simplified work of Matt = (6.2 − 1.6) − 4.4 + 7.8. The error is that he didn't put all decimals inside the parenthesis. => (6.2 − 1.6 − 4.4) + 7.8 = though what he did is acceptable.