yes
Yes.
yes
It must be a generalised rational number. Otherwise, if you select a rational number to multiply, then you will only prove it for that number.
Yes. Any rational number divided by another rational number is also rational.
403 is divisible by no number
403 is composite. It can be evenly divided by 13: 403/13 = 31.
403, 806, 1209, 1612 +403 . . .
It is a rational number. It can be written as a fraction.
yes
Is 12.05 a rational number or irrational number?
1.96 is a rational number
It is a rational number, as it can be written as a fraction.
Any of its factors which are 1, 13, 31 and itself 403
Yes, the sum is always rational.
There is no such thing as a number that is both rational and irrational. By definition, every number is either rational or irrational.
As much as, in these days of uncertainty, anything can be anything. As long as the constraints of a rational number are kept to, a rational number will always remain a rational number.