9 + ( - 8) + 9 + ( - 8) =6 + 9 + ( - 4) + ( - 1) =5 + 3 + ( - 7) + ( - 6) =4 + ( - 1) + 4 + ( - 2) =2 + ( - 9) + ( - 2) + 8 =?
9 + ( - 8) + 9 + ( - 8) = 6 + 9 + ( - 4) + ( - 1) = 5 + 3 + ( - 7) + ( - 6) = 4 + ( - 1) + 4 + ( - 2) = 2 + ( - 9) + ( - 2) + 8 =.