题目内容
计算
3.14×67+8.2×31.4-90×0.314
12.65÷12.5÷0.8
(32×0.63×0.95)÷(1.6×21×1.9)
3.14×67+8.2×31.4-90×0.314
12.65÷12.5÷0.8
(32×0.63×0.95)÷(1.6×21×1.9)
考点:小数的巧算
专题:计算问题(巧算速算)
分析:(1)根据数字特点,把原式变为3.14×67+82×3.14-9×3.14,运用乘法分配律的逆运算简算.
(2)(3)运用除法的性质简算.
(2)(3)运用除法的性质简算.
解答:
解:(1)3.14×67+8.2×31.4-90×0.314
=3.14×67+82×3.14-9×3.14
=3.14×(67+82-9)
=3.14×140
=439.6
(2)12.65÷12.5÷0.8
=12.65÷(12.5×0.8)
=12.65÷10
=1.265
(3)(32×0.63×0.95)÷(1.6×21×1.9)
=(32÷1.6)×(0.63÷21)×(0.95÷1.9)
=20×0.03×0.5
=0.3
=3.14×67+82×3.14-9×3.14
=3.14×(67+82-9)
=3.14×140
=439.6
(2)12.65÷12.5÷0.8
=12.65÷(12.5×0.8)
=12.65÷10
=1.265
(3)(32×0.63×0.95)÷(1.6×21×1.9)
=(32÷1.6)×(0.63÷21)×(0.95÷1.9)
=20×0.03×0.5
=0.3
点评:根据数据特点,运用运算定律运算性质灵活简算.
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