用竖式算一算。1.2-0.3= 1.4+0.8= 6.2+3.8= 8.4+1.9= 6.8-3.4=
206+ 598=
42 :="x" :
求未知数X x-x=
(2.4×1.5-1.5)÷0.7
(3.2+3.2+3.2+3.2) ×2.5