What does the division sign on a prescription mean?

Answer 1

It's actually one circle above a horizontal line and one "1" below it. It means "One tablet". To write "two tablets", he would have drawn two circles above the horizontal line and two "1"s below it.

Answer 2

It's not a division sign it is a T with a dot on top. It means the number 1. Doctors use Roman numerals to indicate numbers. But 1-3 are expressed in other symbols like these. Likewise, 2 is written with 2 capital T's and 2 dots on top(will look like the Greek letter pi with 2 dots on top).