17-9=
32-30=
15+4=
70-40+4=
5+43=
46-6=
29+20=
16-8+20=
70+25=
26+40=
89-7=
42-2-20=
73-70=
7+62=
15-7=
4+3+60=
23+35= 76-73= 88-72= 6+43=
45+345+30 58-358-30 50+1717+50
69-2187-20 3+5555-3 30个一3个十
个长方形
个三角形