42+=67 +36=58 -6=69
+6=94 -21=55 66-=45
+8=78 63-=60
-40=6 2+=72
25+3060 23+2055 47+1069
30+1545 6+630-20 30-1010+15
56-849 31-38+20 1元9角
16-8 11-4 12-7 15-9 17-8
14-9 12-3 16-9 14-6 11-5
□○□=□
2个十是
与15相邻的两个数是和