Question

How to solve 4122-?=373

Answer 1

Just looking at this algebra problem, you can infer that the answer is going to be a positive b/c of the neg variable. 

1) subtract 4122 from 373
-?=   -3749


2) You can't have a neg variable so you multi with neg one
  
Making your answer pos 3749

Answer 2

Since you don't know 4122 - what will give you 373 you have to:
1)  Add 4122 and 373 together
2) that will give you 4495
3) so 4495 is your answer