1+19= 19-12= 15-5= 3+11= 10+7=
19-4= 15+5= 18-9= 17-2= 20-2=
6+11= 18-7= 9-1= 20-10= 3+4=
8-4+14= 5+9-5= 13-5-6= 12-5+6=
2+17+1= 12-1+4= 17-17+9= 12+3+3=
5+4-2= 15-7+2= 16-8-4= 20-6-10=
1+14-15= 9+8-14= 3+14-15= 18-8+1=
1) 13-4= 2) 13-5= 3) 12-4= 4) 13-4=
5) 14-8= 6) 17-9= 7) 10-6= 8) 14-5=
9) 17-9= 10) 12-7= 11) 14-9= 12) 16-8=
13) 11-8= 14) 11-2= 15) 11-5= 16) 12-7=
17) 15-9= 18) 16-8= 19) 13-5= 20) 11-6=
8 + 6 = 7 + 5 = 6 + 5 = 9 + 3 =
14-8= 12-7= 11-6= 12-9 =
14-6= 12-5= 11-5= 12-3 =
8+( )=15 7+( )=13 5+( )=14 6+( )=12
15- 8 = 13-6 = 14-5 =
15-( )= 13-( )= 14-( )= 12-6 =
13+7= 18-9= 5+13= 20-12= 11+8=
20-10= 7+11= 19-12= 18-7= 19-11=
15-2= 15-5= 3+11= 6+9= 4+13=