16-9= 12-7= 6+8= 8+80=
47+3= 64-7= 50+46= 85-50=
77-60= 36+40= 90-7= 25+9=
48-30= 67+7= 85-6= 70+28=
28+9+7= 64-8-30= 30+48-70= 80-20+9=
28+60-9= 8+(26+4)= 82-(79-70)=