27+=80 35-=17 39-12=+12
-6=46 +12=30 45-15=-20
+38=40 -45=29 +26=83 72-=35
25+14=
48-23=
80-25=
100-60-20=
36+24=
50+50=
72+18=
25+10+20=
63-47= 38+26=
75-46-21= 43+(24+18)=