1 58.26-13.6-6.4+17.4
=（58.26+17.4）-（13.6+6.4）
=75.66-20
=55.66
2 564-298=564-300+2=264+2=266第三题呢？ = =3 5/11×[（5/2+1/3）÷5/6]=5/11×[5/2×6/5+1/3×6/5]=5/11×[3+2/5]=5/11×17/5=17/11