12-5 30+9 9+8 48-40 73-3
>>>>
20+7 81-3 64+7 42-40 37-2
>>>>
48=40+ 56-=50 78-=8
53=+3 -7=80 -40=9
+70=74 48-=40
9+=89 -8=60
30+<35 57->50
11-3=
25-5=
14-6+4=
53-3=
8+70=
13-9+10=
66-60=
19-7=
73-70+14=
= (个) = (个)