Then called Pharaoh for Moses and for Aaron and said - Make entreaty unto Yahweh, that he take away the frogs from me and from my people, - and I must lot the people go that they may sacrifice to Yahweh.

So the Israelites did this. Some gathered a lot, some a little.

When they measured it by quarts, the person who gathered a lot had no surplus, and the person who gathered a little had no shortage. Each gathered as much as he needed to eat.