-5.3-3.2+2.5-|-5.7|

这好像不是心理问题吧?不过问了我就解下吧
1 -5.3-3.2+2.5-|-5.7|
=-5.3-3.2+2.5-5.7
=2.5-(5.3+3.2+5.7)
=2.5-14.2
=-11.7
2 -1/2-26/5-1+16/5-4.5-7/3
=-0.5-1-4.5-26/5+16/5-7/3
=-3-10/5-7/3
=-3-2-7/3
=-5-7/3
=-15/3-7/3
=-22/3
3 (+71/4)-(+6.25)-(-17/2)+(-0.75)-(+89/4)
=-6.25-0.75-89/4+71/4+17/2
=-7-18/4+17/2
=-7-9/2+17/2
=-14/2-9/2+17/2
=-6/2
=-3