用简便方法计算下面各题99÷4.5 12÷1.5÷2 1.28×6-1.28-1.28×545×101 4÷2.5 12.5×1.3×0.8.
方法
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(1)99÷4.5,
=99÷9÷0.5,
=11÷0.5,
=22;(2)12÷1.5÷2,
=12÷(1.5×2),
=12÷3,
=4;(3)1.28×6-1.28-1.28×5,
=1.28×(6-1-5),
=1.28×0,
=0;(4)45×101,
=45×100+45×1,
=4500+45,
=4545;(5)4÷2.5,
=(4×4)÷(2.5×4),
=16÷10,
=1.6;(6)12.5×1.3×0.8,
=1.3×(12.5×0.8),
=1.3×10,
=13.
