用简便方法计算 1.4*56.8+4.32*14 2000*199.9-1999*199.8 312.5*12.3-312.5*6.9+312.5

1.4*56.8+4.32*14
=14*5.68+4.32*14
=14*（5.68+4.32）
=14*10
=140
2000*199.9-1999*199.8
=2000*（199.8+0.1）-1999*199.8
=2000*199.8+2000*0.1-1999*199.8
=（2000-1999）*199.8+2000*0.1
=199.8+200
=399.8
312.5*12.3-312.5*6.9+312.5
=312.5*（12.3-6.9+1）
=312.5*6.4
=（25*4）*2*（12.5*0.8）
=100*2*10
=2000
9.56*4.18-7.3*4.18-0.26*4.18
=（9.56-7.3-0.26）*4.18
=2*4.18
=8.36