19.99×19.98-19.97×19.96简便运算快

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/20 12:07:57
19.99×19.98-19.97×19.96简便运算快19.99×19.98-19.97×19.96简便运算快19.99×19.98-19.97×19.96简便运算快(20-0.01)*(20-0.

19.99×19.98-19.97×19.96简便运算快
19.99×19.98-19.97×19.96简便运算

19.99×19.98-19.97×19.96简便运算快
(20-0.01)*(20-0.02)-(20-0.03)*(20-0.04)
=400-0.4-0.2+0.0002-400+0.8+0.6-0.0012
=0.8+0.0002-0.0012
=0.799

=(20-0.01)*(20-0.02)-(20-0.03)*(20-0.04)
=20*20-(0.01+0.02)*20+0.01*0.02-20*20+(0.03+0.04)*20-0.03*0.04
=(0.03+0.04-0.01-0.02)*20+0.01*0.02-0.03*0.04
=0.04*20+0.0002-0.0012
=0.8-0.001
=0.799

19.99×19.98-19.97×19.96
=1999*0.01*1998*0.01-1997*0.01*1996*0.01
=1999*1998*0.01^2-1997*1996*0.01^2
=0.01^2*[(1997+2)(1996+2)-1997*1996]
=0.01^2*[1997*1996+2(1997+1996)+4-1997*1996]
=0.0001*(2*3993+4)
=0.0001*7990
=0.799.