3.4×4.5÷0.17,
=3.4÷0.17x4.5
=20x4.5
=90
7.6÷2.5÷4
=7.6÷(2.5x4)
=7.6÷10=0.76
62.8-36÷7.5这题没有什么简便计算,只有先算乘除后加减了