Six Digits Converter

This is a mathematical book, and you must find the addition of two numbers (each one with six digits) with the given hint of four digits and the sum of the two numbers. For example, you have the question 1 : ( - 8 5 - - - ) - ( - - 6 5 - - ) = 449046, and you have to find the answer 1 : 785633 - 336587 = 449046.