求一道数学题(过程)简便方法3.6x31.4+43.9x6.420.05x39+200.5x4.1+40x10.05

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 08:41:55
求一道数学题(过程)简便方法3.6x31.4+43.9x6.420.05x39+200.5x4.1+40x10.05

求一道数学题(过程)简便方法3.6x31.4+43.9x6.420.05x39+200.5x4.1+40x10.05
求一道数学题(过程)简便方法
3.6x31.4+43.9x6.4
20.05x39+200.5x4.1+40x10.05

求一道数学题(过程)简便方法3.6x31.4+43.9x6.420.05x39+200.5x4.1+40x10.05
3.6x31.4+43.9x6.4
=3.6x31.4+31.4x6.4+12.5x6.4
=31.4x(3.6+6.4)+12.5x8x0.8
=314+100x0.8
=314+80
=394
20.05x39+200.5x4.1+40x10.05
= 20.05x39+20.05x41+40x20.05-40x10
=20.05x(39+41+40)-400
=20.05x120-400
=2005+20.05x20-20x20
=2005+0.05x20
=2006