97又1/50*1/49+77又1/40*1/39+57又1/30*1/29=?

=（97*50+1)/50*1/49+(77*40+1)/40*1/39+(57*30+1)/30*1/29
=4851/50*1/49+3081/40*1/39+1711/30*1/29
=99/50+79/40+59/30
=(2-1/50)+(2-1/40)+(2-1/30)
=6-(1/50+1/40+1/30)
=6-(12/600+15/600+20/600)
=6-47/600
=5又553/600

97又1/50*1/49+77又1/40*1/39+57又1/30*1/29=?
=(98-49/50)*1/49+(78-39/40)*1/39+(58-29/30)*1/29
=98*1/49-49/50*1/49+78*1/39-39/40*1/39+58*1/29-29/30*1/29
=2-1/50+2-1/40+2-1/30
=6-47/600
=5又553/600

=(98-49/50)*1/49+(78-39/40)*1/39+(58-29/30)*1/29
=98*1/49-49/50*1/49+78*1/39-39/40*1/39+58*1/29-29/30*1/29
=2-1/50+2-1/40+2-1/30
=6-47/600
=5又553/600