1.
5/16+(7/8-1/4)+1/2
=5/16+(7/8-2/8)+8/16
=5/16+5/8+8/16
=13/16+10/16
=23/16
2.二十八分之二十五减(七分之二加十四分之五)
25/28-(2/7+5/14)
=25/28-(4/14+5/14)
=25/28-9/14
=25/28-18/28
=7/28
=1/4
3.2x加5x等于0.28 3x减六分之一等于六分之五
2x+5x=0.28 3x-1/6=5/6?
怎么看着这么乱啊
2x+5x=5/6,7x=5/6,x=5/6*1/7=5/42
0.283x-1/6=5/6,0.283x=1,x=1/0.283=1000/283,约为3.5336
好像不对
确定题目是这样吗?