Are the following sentences correct?

Hello, I'm writing a text in English. I don't intend it to be too literary, but I'm looking for very sharp sentences and I’m not familiar with the following expressions. I spare you the rest of the text only consisting of calculations. My intentions or questions are written between [ ]. Thank you. Eternal gratitude.

Rounded to the sharp hours. Rounded to the halves. [or?] Rounded to the half-hours.
Asleep around five o’clock. Waking up at eight o’clock. [meant as a substantive] Up since the the previous afternoon three thirty.
According to an average of eight hours every twenty-four hours. [or?] According to an average of eight hours out of twenty-four hours. [or?] According to an average of eight hours over twenty-four hours. To wit eight hours of sleep for sixteen hours of wake. [or?] Meaning eight hours of sleep for sixteen hours of wake. One for two. [Is there a better alternative than 'to wit' or 'meaning'?]
62 over 175 equals x over 24 meaning 62 over 175 times 24, 62 times 24 4 times 8 and 6 12 120 4 124, 4 2 8 4 6 12 24, 6 times 4 24, 240 and 8 248, 20 40 12 120 6 160, 160, 40 120 par 10 1200 1240, 62 24 1240. 1240 248 8 4 4 8 88 and 2 4 488 1488. 1488. All of it times 175. 1488 times 175 equals 8,50285714. To wit 8 hours and a half [or] Meaning 8 hours and a half. [same question]