Exodus 12:37-39

37The Israelites journeyed from Rameses to Sukkoth. There were about 600,000 men on foot, plus their dependants.

38A mixed multitude also went up with them, and flocks and herds – a very large number of cattle.

39They baked cakes of bread without yeast using the dough they had brought from Egypt, for it was made without yeast – because they were thrust out of Egypt and were not able to delay, they could not prepare food for themselves either.