(1)7.2÷1.8+6.8×0.5,
=4+3.4,
=7.4;
(2)3.7+6.3÷0.6-0.4,
=3.7+10.5-0.4,
=14.2-0.4,
=13.8;
(3)3.5÷[(0.45-0.38)×0.1],
=3.5÷(0.07×0.1),
=3.5÷0.007,
=500;
(4)5.6×7.2+4.4×7.2,
=(5.6+4.4)×7.2,
=10×7.2,
=72.
(1)7.2÷1.8+6.8×0.5,
=4+3.4,
=7.4;
(2)3.7+6.3÷0.6-0.4,
=3.7+10.5-0.4,
=14.2-0.4,
=13.8;
(3)3.5÷[(0.45-0.38)×0.1],
=3.5÷(0.07×0.1),
=3.5÷0.007,
=500;
(4)5.6×7.2+4.4×7.2,
=(5.6+4.4)×7.2,
=10×7.2,
=72.