In ranks - Literally, in the form of square beds in a garden. By regularly formed companies.
By hundreds and by fifties - Some companies had a hundred in them, and some groupings had fifty in them. We do not need to suppose that these were "exactly" formed or arranged, but that this was approximately the number. The expression indicates a "multitude." There were so many that they sat down, by "hundreds" and by "fifties," in separate companies, upon the green grass.

By hundreds, and by fifties - "That is," says Mr. Wesley, "fifty in a rank, and a hundred in file. So, a hundred multiplied by fifty, made just five thousand." But if they sat fifty deep, how could the disciples conveniently serve them with the bread and fish?

And they sat down in (u) ranks, by hundreds, and by fifties.
(u) The word signifies the beds in a garden, and it is literally, "by beds and beds", meaning by this that they sat down in rows one by another, as beds in a garden.

And they sat down in ranks,.... Or "beds": in such form as little beds are placed in a garden, or as rows of vines in a vineyard, in which form the scholars of the wise men sat in their schools: it is said (g),
"R. Eliezer ben Azariah expounded before the wise men in the vineyard (i.e. the university) of Jabneh: though was there a vineyard there? but these are the disciples of the wise men, who are made, or placed, , "rows, rows", or "in ranks", as a vineyard.''
By hundreds, and by fifties; that is, an hundred in "each" bed, or row, and fifty in "each" bed, or row, as the word signifies: each distinct bed, or row, had either a hundred, or fifty in it.
(g) T. Hieros. Beraeot, fol. 7. 4. Vid. Gloss. in T. Bab. Yebamot, fol. 42. 2.

And they sat down in ranks, by hundreds, and by fifties--Doubtless this was to show at a glance the number fed, and to enable all to witness in an orderly manner this glorious miracle.

They sat down in ranks - The word properly signifies a parterre or bed in a garden; by a metaphor, a company of men ranged in order, by hundreds and by fifties - That is, fifty in rank, and a hundred in file. So a hundred multiplied by fifty, make just five thousand.