用简便方法和递等式计算:(1)2005×18-200.5×90+20050×0.1(2)(0.75×2.6×2.7)÷(0.13×0.25×9)(3)(2+3.15+5.87)×(3.15+5.87+7.32)-(2+3.15+5.87+7.32)×(3.15+5.87)
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/15 20:39:03
用简便方法和递等式计算:(1)2005×18-200.5×90+20050×0.1(2)(0.75×2.6×2.7)÷(0.13×0.25×9)(3)(2+3.15+5.87)×(3.15+5.87+7.32)-(2+3.15+5.87+7.32)×(3.15+5.87)
用简便方法和递等式计算:
(1)2005×18-200.5×90+20050×0.1
(2)(0.75×2.6×2.7)÷(0.13×0.25×9)
(3)(2+3.15+5.87)×(3.15+5.87+7.32)-(2+3.15+5.87+7.32)×(3.15+5.87)
用简便方法和递等式计算:(1)2005×18-200.5×90+20050×0.1(2)(0.75×2.6×2.7)÷(0.13×0.25×9)(3)(2+3.15+5.87)×(3.15+5.87+7.32)-(2+3.15+5.87+7.32)×(3.15+5.87)
(1)2005×18-200.5×90+20050×0.1
=2005×18-2005×9+2005
=2005×(18-9+1)
=2005×10
=20050
(2)(0.75×2.6×2.7)÷(0.13×0.25×9)
=(0.75×0.25)×(2.6×0.13)×(2.7÷9)
=3×20×0.3
=18
(3)(2+3.15+5.87)×(3.15+5.87+7.32)-(2+3.15+5.87+7.32)×(3.15+5.87)
=2×(3.14+5.87+7.32)+(3.15+5.87)×(3.15+5.87+7.32)-2×(3.15+5.87)-(3.15+5.87+7.32)×(3.15+5.87)
=2×(3.15+5.87+7.32)-2×(3.15+5.87)
=2×7.32
=14.64