How Did The Israelites Leave Egypt?

(17) And it was when Pharaoh let the people go, God did not lead them by way of the land of the Philistines, although it was nearer; for God said, “The people may have a change of heart when they see war, and return to Egypt.” (18) So God led the people round about, by way of the wilderness at the Sea of Reeds. Now the Israelites went up ??? from the land of Egypt.

There is no hamushim except armed, as it is said, "And the Israelites ascended hamushim" (Joshua 1:14), and it is written "The Reubenites, the Gadites, and the half-tribe of Manasseh went across...About forty thousand shock troops went across..." (Joshua 4:12-13).
Variantly: "hamushim went up from the land of Egypt" - one out of five (['chammishah'] who had been there).
Others say: one out of fifty ('chamishim').

Other says: one out of five hundred ('chamesh me'oth').

Rabbi Nehorai says: "By The Service! Not one in five hundred went up. For it is written, "(In Egypt,) I made you as numerous as the plants of the field"(Ezekiel 16:7), and "And the children of Israel were fruitful, and teemed, and multiplied, and became exceedingly strong, and the land was filled with them" (Exodus 1:7) - a woman would bear six in one birth — and you say one in five hundred went up! The Service! Not one out of 500 ascended, rather many Israelites died in Egypt. And when did they die? In the three days of darkness, as it is said, 'One man did not see another' (Exodus 10:23) - that they buried their dead, and they thanked and praised the Holy One Blessed be He that their enemies did not see and rejoice in their downfall."

There's no hamushim, except armed, as it is said "The Reubenites, the Gadites, and the half-tribe of Manasseh went across hamushim in front of" their brothers (Joshua 4:12) - This teaches us that they ascended prepared for war with five different types of weaponry: bows, alehs(?), shields, spears, and swords.

Another understanding: Some of them ascended in four generations and some of them ascended in five generations.
Another understanding: To teach us that converts and slaves ascended with them - five different types in all.
Another understanding: One out of five went up.
Another understanding: One out of 50.
Another understanding: One out of 500.
Rabbi Nehorai says: "By The Service! It was not one out of 5000! And similarly does it say, 'I let you grow like the plants of the field' (Ezekiel 16:7) - and when did they die? In the days of darkness when the Egyptians were dwelling in darkness and the Israelites buried their dead and they acknowledged and they praised to God since they did not see their enemies in the rejoice in their punishments."

וחמשים — The word חמשים means provided with weapons (Mekhilta d'Rabbi Yishmael 13:19:2). — [Because He led them by a circuitous route through the wilderness He brought it about that they went up from Egypt well-provided; for had He led them circuitously by the route of an inhabited district they would not have provided for themselves every thing that they needed, but only a part, like a person who is travelling from place to place and intends to purchase there whatever he will require. But if he were setting out for the wilderness he must provide all that he will require. — This verse (statement in the verse) is written only with the view of making the ear understand (preparing you for a later statement) viz., that you should not wonder with regard to the war with Amalek and the war with Sihon and Og and Midian where they obtained weapons, since they smote them with the sword]. In a similar sense it says, (Joshua 1:14) “and ye shall pass over armed (חמשים)”. Onkelos, too, translated it by מזרזין which signifies “armed” in Aramaic, just as he translates the word וירק in (Genesis 14:14) וירק את חניכיו which means, “And he armed his trained servants” by וזריז.

Another explanation of חמשים is: only one out of five (חמשה) went forth from Egypt, and four parts of the people died during the three days of darkness because they were unworthy of being delivered (Mekhilta d'Rabbi Yishmael 13:19:3; cf. Rashi on 10:22).