What was the significance of Maniac's actions before he went to sleep the first night he spent at the Beales'?

For a long time, Maniac Magee had not had a home of his own. His parents died when he was young, so he went to live with his aunt and uncle. Their house was full of turmoil because of their troubled marriage, so Maniac did not really feel at home there. For a year after that, he was on his own. Maniac longed for a place to call home.

When Mr. and Mrs. Beale invited...

For a long time, Maniac Magee had not had a home of his own. His parents died when he was young, so he went to live with his aunt and uncle. Their house was full of turmoil because of their troubled marriage, so Maniac did not really feel at home there. For a year after that, he was on his own. Maniac longed for a place to call home.

When Mr. and Mrs. Beale invited Maniac to come stay with them, he did something unusual before going to bed. He got out of bed, walked downstairs, and peeked his head outside the front door. Much to the confusion of Mr. and Mrs. Beale, Maniac "looked at the three cast-iron digits nailed to the door frame: seven two eight. He kept staring at them, smiling." Maniac's heart was filled with joy because "he finally had an address." He said good-night to Mr. and Mrs. Beale, who must have wondered about the peculiar behavior of their young houseguest. He went back upstairs, feeling satisfied.