Exodus 6:18

ושני חיי קהת … ושני חיי עמרם וגו׳ AND THE YEARS OF THE LIFE OF KOHATH WERE etc. … AND THE YEARS OF THE LIFE OF AMRAM WERE etc. — From these numbers we may gather regarding the period of residence of the children of Israel, — viz., four hundred years, of which Scripture speaks, that these four hundred years were not passed in Egypt alone, but that they date from the day of Isaac’s birth. You know that Kohath was one of those who went down to Egypt; now reckon all his years (133) although really we should not take into account the years he lived before he went down to Egypt, and the years of Amram, his son (137), and the eighty years of Moses, the latter’s son, which he had attained when the Israelites left Egypt, and you will not find them totaling to four hundred, and in this calculation many years of the sons’ ages are included in those of their fathers (i. e. in such a calculation one must deduct in each instance the father’s age when his son was born since this number is included in the total age of each of these persons) (cf. Rashi on Exodus 12:40)

וּבְנֵ֣י קְהָ֔ת עַמְרָ֣ם וְיִצְהָ֔ר וְחֶבְר֖וֹן וְעֻזִּיאֵ֑ל וּשְׁנֵי֙ חַיֵּ֣י קְהָ֔ת שָׁלֹ֧שׁ וּשְׁלֹשִׁ֛ים וּמְאַ֖ת שָׁנָֽה׃

And the sons of Qehat, ῾Amram, and Yiżhar, and Ḥevron, and ῾Uzzi᾽el; and the years of the life of Qehat were a hundred and thirty three years.