Answer :

-90.85 = -90 85/100
-90 85/100 = -90 17/20
Well, -90 would obviously be the whole number.
So, [tex]-90 \frac{unknown}{unknown} [/tex].
And now, 85 would be a part, so that would be the numerator. The last number of 85, 5, is in the hundredth place, so the denominator would be 100.

Which would get us, [tex]-90 \frac{85}{100} [/tex]

Now simplify.
5 can go into both numbers.

85/5 = 17
100/5 = 20

So you get [tex] \frac{17}{20} [/tex]

Your final answer is [tex]-90 \frac{17}{20} [/tex]