One learner evaluates -5 + 8 + (-6) as 3, stopping after the opening pair of terms. What is the correct value?

Explication

Working from the left, -5 + 8 reaches three, and the remaining addend then moves six steps further left to finish below zero. Leaving that final move out stops the work halfway and reports a running total as though it were the finished sum, while dropping the minus sign on the opening term instead gives seven.