2.4*5.8+0.28*4.2简便算法
问题描述：
2.4*5.8+0.28*4.2简便算法
199.7*19.98-199.9*19.96
答
2.4*5.8+0.28*4.2=2.4*(5.8+4.2)-(2.4-0.28)*4.2=24-2.12*4.2=24-2.1*4.2-0.02*4.2=24-8.82-0.084= ...199.7*19.98-199.9*19.96=0.001*(1997*1998-1999*1996)=0.001*[(1998-1)*1998-(1998+1)*(1998-2)]=0.001*[-1998...