When Israel entered Egypt there were 70 of them, not counting Joseph and his Egyptian family.
Not exactly sure the time frame between verse 7 and verse 8 but apparently there was enough time that had elapsed that the people and the pharaoh did not know of Joseph or the things that he did for Egypt. This little piece of history could have saved the Israelites from a life of slavery, but as we learn in our society some of history is left out and we never learn from it.
The more the Israelites were oppressed the more they multiplied. God blessed them with families even in their tough time. Why, with all of the numbers of Israelites, did they allow themselves to be taken as slaves. They very easily could have overtaken the Egyptians. I know I know God had them right where He wanted them, but still looking back you wonder why they did not stick up for themselves. God would have used that too, Right????
I don't understand why they let the girls live and the boys they were to kill. If there were no girls there would not be any more Israelites eventually.
So sad that what we don't understand we fear. We think we would learn from reading history both Biblical and secular that we would get past that, but apparently not. We probably think that situations like that could not happen to us.