Question

find the difference 5-6 -7 12

Answer 1

Ok, if there are not any parentheses, and we do the problem in order, we would do it like this: 5-6-7-12. The answer would be -20. 

Answer 2

If there is no parentheses at all you would do it like this:5-6-7-12. After it would be -20 because 5-6 is -1 and -7-12 is -19. -1-19 would be -20. Ask anytime;)