(1)6.48÷0.12÷5.4,=54÷5.4,=10;(2)9.36×9÷1.8,=84.24÷1.8,=46.8;(3)9.728÷3.2+6.4,=3.04+6.4,=9.44;(4)39.05÷7.1-4.02,=5.5-4.02,=1.48.