108-271+215-_____=-103 Im going to combine the first thee numbers and replace the blank with a variable, lets use x. 52 - x=-103 now I am going to subtract 52 on both sides to get the variable alone -x=-155 Im going to multiply both sides to eliminate the negitive in the variable x=155 If you want to check just plug 155 into the blank 108-271+215-155=-103 -163+215-155=-103 52-155=-103 -103=-103