1、354*442-353*443
=(353+1)*442-353*443
=353*442+442-353*443
=353*(442-443)+442
=-353+442
=89
2、64*103-59*64+56*64
=64*(103-59+56)
=64*100
=6400
3、2004-2003+2002-2001+.+2-1
=1+1+1+...+1
=1×2004÷2
=1002
1、354*442-353*443
=(353+1)*442-353*443
=353*442+442-353*443
=353*(442-443)+442
=-353+442
=89
2、64*103-59*64+56*64
=64*(103-59+56)
=64*100
=6400
3、2004-2003+2002-2001+.+2-1
=1+1+1+...+1
=1×2004÷2
=1002