How many things here is God said to “divide” (as at Gen 1:4), and so, what might its significance be?

God is said to divide light from darkness (Gen 1:4); the waters under the sky (the sea) from those above (the clouds, I think; 1:7); day from the night (1:14); light from darkness again (1:18), but on my interpretation this really is the same insofar as it is the sun’s light, whether obscured by the proto-earth’s clouds or not, that performs this function. Moreover, although the text does not explicitly say so, the land is clearly “divided” from the sea (1:9). These “divisions” seem to distinguish the main components of the visible universe, which was at first “without form.” Hence with these actions God gives form to the world.