As a ratio it's fine. As blood pressure, you need to be under your doctor's care.
No, that's very high.
Zero over 213 is zero. This is the same for zero over anything.
No, something is wrong.
92 over 80 is simplified as 23 over 20.
divide 213 by 12 and the quotient is the wholes and the remainder is the numerator and 12 is the denominator.
213/532
28/92 = 30.4348%
213 days.213 days.213 days.213 days.213 days.213 days.213 days.213 days.213 days.213 days.213 days.
-53/20 = -213/20
92/1500 = 23/375
92/260 = 23/65
16/92 = 4/23