Exodus 1:5 - The Bible is good on math....

We are reminded of God’s accurate head count with this verse. He knows every soul in heaven and hell also.

Exodus 1:5  And all the souls that came out of the loins of Jacob were seventy souls: for Joseph was in Egypt already.

Exodus 1:5 Gill

And all the souls that came out of the loins of Jacob were seventy souls,.... "Souls" are put for persons; of the number seventy, and how reckoned; see Gill on Gen 46:27. This was but a small number that went down to Egypt, when compared with that which went out of it; and that it should be compared with it is the design of its being mentioned, see Exo 12:37,

for Joseph was in Egypt already; and is the reason why he is not reckoned among the sons of Jacob, that came thither with him; though rather it may be better rendered, "with Joseph who was in Egypt" (c); for he must be reckoned, and indeed his two sons also, to make up the number seventy; therefore Jonathan rightly supplies it,"with Joseph and his sons who were in Egypt,''See Gill on Gen 46:27.

(c) ויסף "cum Josepho qui erat in Aegypto", Junius & Tremellius, Ainsworth, Noldius, No. 1197. p. 273. so the Arabic version, Kimchi, and Ben Melech.

Gen 46:26 All the souls that came with Jacob into Egypt, which came out of his loins, besides Jacob's sons' wives, all the souls were threescore and six;
Gen 46:27 And the sons of Joseph, which were born him in Egypt, were two souls: all the souls of the house of Jacob, which came into Egypt, were threescore and ten.

Gill wrote:
all the souls were threescore and six; thirty two of Leah's, leaving out Er and Onan, sixteen of Zilpah's, fourteen of Rachel's, and seven of Bilhah's, make sixty nine; take out of them Joseph and his two sons, who were in Egypt before, and you have the exact number of sixty six.

And the sons of Joseph, which were born in Egypt, were two souls,.... Ephraim and Manasseh; which is observed to show that they do not come into the above reckoning, but are to be taken into another that follows:

all the souls of the house of Jacob, which came into Egypt, were threescore and ten; here it may be observed, the phrase is varied; it is not said, "all the souls which came out of the loins of Jacob", but "all the souls of the house" or family of Jacob; all that that consisted of, and takes in Jacob himself, the head of his house or family; nor is it said, "which came with Jacob into Egypt", as before, but "which came into Egypt"; not which came with him thither, but yet were there by some means or another, as Joseph and his two sons; Joseph by being brought down, and sold there, and his two sons by being born there; if therefore Jacob, Joseph, and his two sons, are added to the above number of sixty six, it will make seventy; as for the account of Stephen, making the number seventy five; see Gill on Act 7:14.