89又17/18×(-9)
=(90-1/18)×(-9)
=-9×90+1/18×(-9)
=-810-1/2
=-810又1/2
(2/3-4/9+5/27)27-1又1/17×8+1/17×8
=2/3×27-4/9×27+5/27×27-(18/17-1/17)×8
=18-12+5-1×8
=11-8
=3
89又17/18×(-9)
=(90-1/18)×(-9)
=-9×90+1/18×(-9)
=-810-1/2
=-810又1/2
(2/3-4/9+5/27)27-1又1/17×8+1/17×8
=2/3×27-4/9×27+5/27×27-(18/17-1/17)×8
=18-12+5-1×8
=11-8
=3