一减去零点一二加二分之一减去零点三四加三分之一减去零点五六加五分之一减去零点七八等于多少？

1-0.12+1/2-0.34+1/3-0.56+1/5-0.78
=1-（0.12+0.78）-（0.34+0.56）+1/2+1/3+1/5
=1-1.8+0.5+0.25+1/3
=1/3-0.05=17/60

1-0.12+1/2-0.34+1/3-0.56+1/5-0.78
=1-(0.12+0.78)-(0.34+0.56)+1/2+1/3+1/5
=1-0.9-0.9+1/2+1/3+1/5
=1+31/30-1.8
=61/30-54/30
=7/30

1-0.12+1\2-0.34+1\3-0.56+1\5-0.78=
1+1\2+1\3+1\5-0.12-0.34-0.56-0.78=
1+15\30+10\30+(5\30+1\30)-1.8=
0.2+1\30=7\30

1-0.12+1/2-0.34+1/3-0.56+1/5-0.78
=1-(0.12+0.78)-(0.34+0.56)+1/2+1/3+1/5
=1-0.90-0.90+0.5+1/3+0.2
=1.7-1.8+1/3
=1/3-0.1
=1/3-1/10
=7/30
就因为结果相同，就不让我回答了
可恶！ 这系统真烂
这回不同了

不知道简便算法是什么意思?直接算都很简单

1-0.12+1/2-0.34+1/3-0.56+1/5-0.78
=1+(1/2+1/3+1/5)-(0.12+0.78)-(0.34+0.56)
=1+31/30-0.9-0.9
=31/30-4/5
=7/30