For example, if we have 4/5 --> we can just use division to obtain 0.8. Another way to tackle this would be to divide something into 5 equal slices for a total of 100%. Each slice would then be 20% and 20 X 4 = 80% --> 0.8.
If we have 99/100 --> notice that the denominator is 100, so we can just directly do the following: 99.0* --> 0.99 by moving the decimal place two places to the left.
*Note that the example does not explicitly state 99.0 but 99 is the same as 99.0. The decimal point is just invisible.