计算：(-2又3⼀4)-(-1又1⼀2)；( 2⼀7) (-4⼀9)-( 5⼀9)-( 1)；(-5⼀12)*8⼀15*1⼀2*(-2⼀3)：(-1)*(-5⼀4))*8⼀15...

(1).原式=(-11/4)+(3/2)=(6/4)-(11/4)=-5/4=-1又1/4
(2).原式=(-8/63)-(5/9)-1=(-8/63)-(35/63)-(63/63)=-(8+35+63)/53=-106/63=-1又43/63
(3).原式=-2/(3*3*3)=-2/27，（约分可得）
(4).原式=0，任何数乘以0均为0

（-2又3/4)-(-1又1/2) (2/7)(-4/9)-(5/9)-(1) (-5/12)*8/15*1/2*(-2/3) (-1)*(-5/4)*8/15*3/2*(-2/3)*0*(-1)
=-2又3/4-1又2/4 = 2/7-4/9-5/9-1 =(-2/9)*1/2*(-2/3) =0
=-4又1/4 =8/63-14/9 =2/27 (因为0乘任何数都得0)
=-106/63

(-2又3/4)-(-1又1/2)
=-11/4+3/2
=-5/4
( 2/7) (-4/9)-( 5/9)-( 1)
=-8/63-14/9
=-106/63
(-5/12)*8/15*1/2*(-2/3)
=(-5*8*1*(-2))/(12*15*2*3)
=2/27
(-1)*(-5/4))*8/15*3/2*(-2/3)*0*(-1)
=0