—(2/13+8/15)+(2/13-7/15)简便计算
问题描述:
—(2/13+8/15)+(2/13-7/15)简便计算
答
2/13-7/15-2/13-8/15=-7/15-8/15=-1
答
=-2/13+8/15+2/13-7/15
=-2/13+2/13+8/15-7/15
=1/15
答
—(2/13+8/15)+(2/13-7/15)
=-2/13+2/13-(8/15+7/15)
=0-1
=-1
答
—(2/13+8/15)+(2/13-7/15)
=—2/13-8/15+2/13-7/15
=(—2/13+2/13)-(8/15+7/15)
=0-1
=-1