1.8×[6又5/12÷16+(9-2又7/12)]÷2又3/4原式=1.8×[6又5/12÷16+(8又12/12-2又7/12)]÷2又3/4=1.8×（6又5/12÷16+6又5/12）÷2又3/4=1.8×（6又5/12×1/16+6又5/12×1）÷2又3/4=1.8×6又5/12×（1/16+1）÷2又3/4...