48-30= +9 43-30= +6 5+ =64-50 15- =38-30 27-10=8+ 71-60=8+ 13- =26-20 5+ =32-20
48-30=9+9 5+9=64-50 27-10=8+9 13-(-3)=26-20 43-30=7+6 15-(-3)=38-30 71-60=8+3 5+7=32-20
48-30 = 9+9; 5+9=64-50; 27-10=8+9; 13-7=26-20; 43-30=7+6; 15-7=38-30; 71-60=8+3; 5+7=32-20