(50+6)+7 = 50+(6+7) = 50+13 = 63
(30+8)+4 = 30+(8+4) = 30+12 = 42
(30+9)+5 = 30+(9+5) = 30+14 = 44
(40+3)+9 = 40+(3+9) = 40+12 = 52
(70+7)+8 = 70+(7+8) = 70+15 = 85
(60+6)+6 = 60+(6+6) = 60+12 = 72
56+(4+3) = (56+4)+3 = 60+3 = 63
39+(1+5) = (39+1)+5 = 40+5 = 45
77+(3+5) = (77+3)+5 = 80+5 = 85
38+(2+2) = (38+2)+2 = 40+2 = 42