递等式计算,能简算的就简算.
(1)1.25×8.08
(2)49.5÷7.5+49.5÷2.5
(3)15.7×1.3+14.3×1.3
(4)(1.8-1.8×0.9)÷(0.38-0.28)
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解:(1)1.25×8.08,
=1.25×(8+0.08),
=1.25×8+1.25×0.08,
=10+0.1,
=10.1;
(2)49.5÷7.5+49.5÷2.5,
=6.6+19.8,
=26.4;
(3)15.7×1.3+14.3×1.3,
=(15.7+14.3)×1.3,
=30×1.3,
=39;
(4)(1.8-1.8×0.9)÷(0.38-0.28),
=1.8×(1-0.9)÷0.1,
=1.8×0.1÷0.1,
=1.8.
解析分析:(1)把8.08看作8+0.08,运用乘法分配律简算;
(2)先算除法,再算加法;
(3)运用乘法分配律简算;
(4)第一个括号运用乘法分配律简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.