Infinitely many.
Start with integer addition:
... -5+50, -4+49, -3+48, -2+47, -1+46, 0+45, 1+44, 2+43, ... extending infinitely far in both directions.
Then add numbers to 1 decimal place:
... -5.1+50.1, and so on.
and then numbers to 2 decimal places, 3 dp, and so on, to infinitely many decimal places.
Then consider multiplication and division.
And all that is just for pairs of numbers. You can, of course, extend to triplets and quads, and so on.
the way you make it into a fraction is 45/100
8
45 with 7 left over 457 - 7 = 450 = 10 x 45
.45
There are 13 ways.
the way you make it into a fraction is 45/100
45
20*45 = 900
45.
45
It takes four times because 45+45=90+45=135+45=180. So all of those angles can make a straight line.
Number of combinations = 45C6 = 45!/6!(45-6)! = 8,145,060
45
45
there are 45 different types of dogs in Australia
45 is an integer, not a fraction and there is no sensible way to express it as a fraction.
over 45