Why is this translated as forty days and forty nights, instead of four days and four nights?
6. LN 67.78–67.117 unit: אַרְבַּע יוֹם וְ־ אַרְבַּע לַיְלָה (ʾǎr·bǎʿ yôm w- ʾǎr·bǎʿ lǎy·lā(h)) long time, formally, forty days and forty nights, i.e., a relatively long indefinite period of time (Ex 34:28), note: some sources do not take as an idiom;
LN Louw-Nida Greek-English Lexicon
Swanson, J. (1997). Dictionary of Biblical Languages with Semantic Domains : Hebrew (Old Testament) (electronic ed.). Oak Harbor: Logos Research Systems, Inc.