(-4/9)+(+4/5)-(+5/6)-(+9/10)-(1又5/18)
=-4/9+4/5-5/6-9/10-23/18
=(8/10-9/10)-(8/18+15/18+23/18)
=-1/10-23/9
=-2又59/90（+11）+（-1/2）+（+7）+（-1/6）+（+2）+（-1/3）？采纳我，重新问