There were 430 years from Abram’s 75th year when he entered Canaan, to the Exodus (Exo 12:40-41, see Biblical Chronology Question for a detailed analysis).
Now the sojourn of the children of Israel who lived in Egypt was four hundred and thirty years. And it came to pass at the end of the four hundred and thirty years—on that very same day—it came to pass that all the armies of the Lord went out from the land of Egypt. Exo 12:40-41
Brethren, I speak in the manner of men: Though it is only a man’s covenant, yet if it is confirmed, no one annuls or adds to it. 16 Now to Abraham and his Seed were the promises made. He does not say, “And to seeds,” as of many, but as of one, “And to your Seed,” who is Christ. 17 And this I say, that the law, which was four hundred and thirty years later, cannot annul the covenant that was confirmed before by God in Christ, that it should make the promise of no effect. 18 For if the inheritance is of the law, it is no longer of promise; but God gave it to Abraham by promise. Gal 3:15-18
And God gave the promise to Abraham in his 75th year, Gen 11:32, 12:1. The Law was given on Mt. Sinai just 3-1/2 months from the Exodus, which Shavuot celebrates every year, in the seven Sabbaths from the Passover (the Exodus), Exo 19:1.
430 minus 25 yrs, the years to the birth of Isaac, Gen 21:5; = 405 yrs.
405 minus 60 yrs, the years to the birth of Jacob, Gen 25:26; = 345 yrs.
345 minus 91 yrs, the years to the birth of Joseph, as follows:
Joseph was 30 years when he stood before Pharaoh, Gen 41:46. After 7 yrs of plenty and 2 of famine, with 5 left to the famine, Joseph was revealed to his brothers, and his father Jacob came down to Egypt, when Joseph was 39 yrs, that is, 30 yrs + 7 of plenty + 2 of famine, Gen 45:6. When Jacob came into Egypt, he was 130 yrs old, Gen 47:9.
130 minus 39 = 91 yrs when Joseph was born.
345 minus 91 yrs, the years to the birth of Joseph; = 254 yrs.
254 minus 110 yrs, the years to the death of Joseph, Gen 50:22; = 144 yrs.
The Exodus took place in Moses’ 80th year, Exo 7:7. If we subtract the years of Moses at the Exodus, 80 yrs, from the years left at the death of Joseph, 144 yrs, we will get the number of years between the death of Joseph, under the Pharaohs who knew him, to the birth of Moses, under the Pharaohs who knew not Joseph:
144 yrs minus 80 yrs = 64 yrs only between Joseph and Moses.
The accurate history recorded in Scripture simply explodes the exaggerated years of Manetho, and corrects the erroneous Egyptian chronology, which even Bible believers have compromised with.