7+42= 70-20= 28-20= 38-5=
4+52-30= 16-8= 18+60= 24+4=
60-30= 69-50-3= 44+4= 88-80=
12-8= 40+56= 12-7+6= 46-3=
22+6= 86-60= 90-40= 9+3-8=