Got it. Total guessing, please don't post puzzles like this.
HINT: The 6 in the bottom row is the smile and is in the centre, the two rows above are just the rest of the smile. Rows 1-3 are symmetrical if you ignore the last column. Row 7's two is in the centre, row 6's one is diagonally up and to the right of it.
HINT:
The 6 in the bottom row is the smile and is in the centre, the two rows above are just the rest of the smile.
Rows 1-3 are symmetrical if you ignore the last column.
Row 7's two is in the centre, row 6's one is diagonally up and to the right of it.