3400-62*34-38*20-38*14和999*1999+900的简算过程,急,

3400-62*34-38*20-38*14
=3400-62*34-38*（20+14)
=3400-34*(62+38)
=3400-3400
=0
999*1999+900
=(1000-1)*1999+900
=1999000-1999+900
=1997901

3400-62*34-38*20-38*14
=34*100-34*62-38*34
=34*38-34*38
=0
999*1999+900
=999*2000-999+900
=（1000-1）*2000-99
=2000 000-2000-99
=2000 000-2099
=1997901