15.8/2.5-0.32*6
=6.32-1.92
=4.4
14.5-4.5/0.6-7
=14.5-7.5-7
=7-7
=0
（12.4-6.9）*2.6/1.3
=5.5*2.6/1.3
=14.3/1.3
=11
[13.8-(4.5+7.8)]/0.3
=(13.8-12.3)/0.3
=1.5/0.3
=5