This excerpt of Death of a Salesman gives us a first look inside the dynamics of the Loman marriage. This marriage is one where Willy Loman is the dominant party while his wife, Linda, is the unquestionable enabler. They both play a part: Willy pretends to be doing well, and Linda pretends to believe him. In all, the two conceal many truths from each other that could very well be used to help the marriage, rather than to shield it from stress. In the end, it all indicates that Willy's superficial view of life has grown with him until this day.
In the dialogue above, Willy had just return from work and began to tell one of his fantastic stories Linda about how great he did during his selling trip. This allows Willy to put himself in a position of power as a a successful head of household. He tells Linda that he made "five hundred gross in Providence", which prompts Linda to immediately take out her pencil to calculate Willy's commission. When she comes up with the amount of $212, we see Willy slowly coming back to reality. The money is very needed in the household and he is simply not making any. He now knows that,if he is claiming all those profits, he will have to come up with them. This is when he suddenly changes his story.
WILLY: Well, I—I did—about a hundred and eighty gross in Providence. Well, no—it came to—roughly two hundred gross on the whole trip.
These are dramatic differences from one discourse to another, yet, Linda accepts them as minor mistakes from Willy and, quietly, she accepts everything that he says as a fact. So accepting and used to Willy is Linda, that she does not even mind what comes next: Willy's poor excuse which, in itself, is yet another lie that he uses to expiate himself from any blame.
WILLY: The trouble was that three of the stores were half closed for inventory in Boston. Otherwise I woulda broke records.
This has been the usual behavior between them, however, and so Willy finds no problem in coming up with stories, even if it is to his own wife. He knows that Linda is submissive enough to accept anything he says and make it real for herself. These dynamics are not necessarily malicious from either part, but they do denote a relationship that is, ultimately, dysfunctional and based on lies. It symbolic of the shallow nature of Willy Loman's life which now he transfers onto his family.