7.58+2.42×1.5
=7.58+3.63
=11.21
8÷[（40.75-9.5）×0.4]
=8÷[31.25×0.4]
=8÷12.5
=0.64
3.5×3.5+3.5+3.5
=3.5×(3.5+1+1)
=3.5×5.5
=19.25
图解如下：
图解
3.5x3.5-（3.5+3.5）=12.25-7=5.25
