3.6×2.7+18×0.56-1.8×10% 1998又8/9+1999又8/9+2000又8/9+2001又8/9+2002又8/9+5/9

（1）[3.6×2.7+18×0.56-1.8×10%]÷10%
=[1.8x2x2.7+1.8×5.6-1.8×0.1]x10
=[1.8(5.4+5.6-0.1)]x10
=[1.8(10-0.1)]x10
=[18-0.18]x10
=178.2
(2)1998又8/9+1999又8/9+2000又8/9+2001又8/9+2002又8/9+5/9
=(1998+1999+2000+2001+2002)+(8x5+5)/9
=[(1998+2+1999+1+3x2000)+5
=5x2000+5
=10005
(3)若2!=2×3 ；3!=3×4×5 ；5!=5×6×7×8×9 .
按照题目所给规则,
则 4!=4×5×6×7=840
6!=6×7×8×9×10×11=332640
4!/6!=840/332640这三道题我已经琢磨出来了,不过还是谢谢你.